Systems for assessing athletic performance

ABSTRACT

Sensors detects loft time, speed, power and/or drop distance of a vehicle and/or person. The sensors couple with multiple persons during athletic activity. Data from the sensors downloads to a database so that users may compare athletic performances (e.g., speed) between the persons, such as through the Internet.

RELATED APPLICATIONS

[0001] This application is a continuation of, and claims priority to,commonly-owned and co-pending U.S. application Ser. No. 09/992,966,filed on Nov. 6, 2001, which is a continuation of U.S. application Ser.No. 09/089,232 (now U.S. Pat. No. 6,539,336), filed on Jun. 2, 1998,which claimed priority to U.S. provisional application No. 60/077,251,filed Mar. 9, 1998, and which is a continuation-in-part of U.S.application Ser. No. 08/867,083 (now U.S. Pat. No. 6,266,623), filed onJun. 2, 1997, and which is a continuation-in-part of U.S. applicationSer. No. 08/764,758 (now U.S. Pat. No. 5,960,380), filed Dec. 12, 1996,which is a continuation of U.S. application Ser. No. 08/344,485 (nowU.S. Pat. No. 5,636,146), each of the foregoing applications beingexpressly incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The invention relates generally to monitoring and quantifyingsport movement (associated either with the person or with the vehicleused or ridden by the person), including the specific parameters of“air” time, power, speed, and drop distance. The invention also has“gaming” aspects for connecting users across the Internet. The inventionis particularly useful in sporting activities such as skiing,snowboarding, mountain biking, wind-surfing, skate-boarding,roller-blading, kayaking, racing, and running, in which sporting personsexpend energy, catch “air”, move at varying speeds, and perform jumps.

BACKGROUND OF THE INVENTION

[0003] It is well known that many skiers enjoy high speeds and jumpingmotions while traveling down the slope. High speeds refer to the greaterand greater velocities which skiers attempt in navigating the slopesuccessfully (and sometimes unsuccessfully). The jumping motions, on theother hand, include movements which loft the skier into the air.Generally, the greater the skier's speed, the higher the skier's loftinto the air.

[0004] The interest in high speed skiing is apparent simply by observingthe velocity of skiers descending the mountain. The interest in the loftmotion is less apparent; although it is known that certain enthusiasticsnowboarders regularly exclaim “let's catch some air” and other assortedremarks when referring to the amount and altitude of the lofting motion.

[0005] The sensations of speed and jumping are also readily achieved inother sporting activities, such as in mountain biking, skating,roller-blading, wind-surfing, and skate-boarding. Many mountain bikersand roller-bladers, like the aforementioned skiers, also crave greaterspeeds and “air” time.

[0006] However, persons in such sporting activities only have aqualitative sense as to speed and loft or “air” time. For example, atypical snowboarder might regularly exclaim after a jump that she“caught” some “big sky,” “big air” or “phat air” without everquantitatively knowing how much time really elapsed in the air.

[0007] Speed or velocity also remain unquantified. Generally, a personsuch as a skier can only assess whether they went “fast”, “slow” or“average”, based on their perception of motion and speed (which can begrossly different from actual speed such as measured with a speedometeror radar gun).

[0008] There are also other factors that sport persons sometimes assessqualitatively. For example, suppose a snowboarder skis a double-diamondski slope while a friend skis a green, easy slope. When they both reachthe bottom, the “double-diamond” snowboarder will have expended moreenergy than the other, generally, and will have worked up a sweat; whilethe “green” snowboarder will have had a relatively inactive ride downthe slope. Currently, they cannot quantitatively compare how rough theirjourneys were relative to one another.

OBJECTS OF THE INVENTION

[0009] It is, accordingly, an object of the invention to provide systemsand methods for determining “air” time associated with sport movements.

[0010] It is another object of the invention to provide systems andmethods for determining the speed of participants and/or vehiclesassociated with sport movements.

[0011] It is yet another object of the invention to provide improvementsto sporting vehicles which are ridden by sporting participants, andwhich provide a determination of speed, airtime, drop distance and/orpower of the vehicle.

[0012] Still another object of the invention is to provide systems andmethods for determining the amount of “power” or energy absorbed by aperson during sporting activities. One specific object is to provide agauge of energy spent by a sporting participant as compared to others inthe same sport, to provide a quantitative comparison between two or moreparticipants.

[0013] Yet another object of the invention is to provide the “dropdistance” associated with a jump; and particularly the drop distancewhich occurs within “airtime”.

[0014] Still another object of the invention is to provide a gamingsystem to quantitatively compare airtime, drop distance, power, and/orspeed between several participants, regardless of their location.

[0015] These and other objects of the invention will become apparent inthe description which follows.

SUMMARY OF THE INVENTION

[0016] As discussed herein, “air” or “loft” time (or “airtime”) refer tothe time spent off the ground during a sporting movement. For example,airtime according to the invention can include a snowboarder catchingair off of a mogul or a ledge. Typically, airtime is greater thanone-half (or one-third) second and less than six seconds. In “extreme”sporting events, the maximum airtime can increase up to about ten orfifteen seconds.

[0017] In most cases, it is useful to specify the lower and upper limitsof airtime—e.g., from one second to five seconds—so as to reduceprocessing requirements and to logic out false airtime data. Moreparticularly, the following description provides several techniques andmethods for determining airtime. One technique, for example, monitorsthe vibration of the user's vehicle (e.g., a ski or snowboard) moving onthe ground; and senses when the vibration is greatly reduced, indicatingthat the vehicle is off the ground. However, when such a user stands inline for the chair-lift, she might remain motionless for thirty secondsor more. By restricting the upper limit to five seconds, a system of theinvention can be made to ignore conditions such as standing in line.Similarly, when a user walks slowly, there are cyclical periods ofrelatively small vibration (e.g., when the user lifts his foot off theground). Therefore, a lower limit of one-half second or one second areappropriate; so that any detected “airtime” that falls below that lowerlimit is ignored and not stored.

[0018] In another aspect of the invention, the measurement of airtime isused to quantify the efficiency by which a person or sport vehicleremain on the ground. By way of example, speed skiers desire to remainon the ground; and the invention thus provides a system which monitorsthe person and/or vehicle (e.g., the slalom ski) to detect airtime. Thisinformation is fed back to the person (in real time or in connectionwith a later review of video) so that he or she can improve theirposture to reduce unwanted airtime. In such applications, airtime istypically less than about three or four seconds; and the lower limit isessentially zero (that is, providing miniscule airtime data can beappropriate for training purposes).

[0019] As used herein, “power” refers to the amount of energy expendedby a person or vehicle during a sporting activity, typically over aperiod such as one ski run. The following description provides severalsystems, techniques and methods for determining power. Power need notcorrespond to actual energy units; but does provide a measure of energyexpended by the person or vehicle as compared to other persons andvehicles in the same sporting activity. Power can be used to quantify“bragging rights” between sport enthusiasts: e.g., one user can quantifythat he expended more energy, or received more “punishment”, as comparedto a friend. Power can refer to the amount of “G's” absorbed during agiven period of activity. Power is typically quantified over a periodthat is selectable by the user. For example, power can be determinedover successive one-second periods, or successive five second periods,or successive one minute periods, or successive five minute periods, orother periods. Power can also be measured over a manually selectedperiod. For example, two snowboarders can initialize the period at thebeginning of a run down a ski slope and can stop their period at the endof the run.

[0020] “Speed” refers the magnitude of velocity as measured during asport activity. Speed generally refers to the forward direction of themoving sportsman.

[0021] “Drop distance” refers to the height above the ground asexperienced by a user or vehicle during a sport activity. Drop distancepreferably corresponds to a measured airtime period. For example, asnowboarder who takes a jump off of a ledge might drop thirty feet (dropdistance) in three seconds (airtime). Drop distance can alsospecifically refer to maximum height above the ground for a given jump(for example, a user on a flat surface can first launch upwards off ajump and return to the same level but experience a five foot dropdistance).

[0022] The invention thus provides systems and methods for quantifyingairtime, power, speed and/or drop distance to quantify a user's sportmovement within one or more of the following activities: skiing,snowboarding, wind-surfing, skate-boarding, roller-blading, kayaking,white water racing, water skiing, wake-boarding, surfing, racing,running, and mountain biking. The invention can also be used to quantifythe performance of vehicles upon which users ride, e.g., a snowboard orski or mountain bike.

[0023] The following U.S. patents provide useful background for theinvention and are herein incorporated by reference: U.S. Pat. No.5,343,445; U.S. Pat. No. 4,371,945; U.S. Pat. No. 4,757,714; U.S. Pat.No. 4,089,057; U.S. Pat. No. 4,722,222; U.S. Pat. No. 5,452,269; U.S.Pat. No. 3,978,725; and U.S. Pat. No. 5,295,085.

[0024] In one aspect, the invention provides a sensing unit whichincludes a controller subsystem connected with one or more of thefollowing sensors (each of which is described herein): an airtimesensor, a speed sensor, a power sensor, and a drop distance sensor. Thecontroller subsystem includes a microprocessor or microcontroller andcan include preamplifiers and A/D converters to interface with thesensor(s) (alternatively, the sensor contains such circuitry). Thecontroller subsystem can further include logic circuitry and/or softwaremodules to logic out unwanted data from the sensors (e.g., airtime datathat does not correspond to reasonable loft times). Preferably, thecontroller subsystem also includes digital memory to store parametersfor the sensors and to store data such as power, airtime, speed and dropdistance (collectively “performance data”) for later retrieval. Abattery typically is used to power the controller subsystem. The batterycan also be used for the sensors, if required. However, one preferredsensor which can function for any of the sensors is the piezoelectricfoils such as made from AMP SENSORS™. These foils do not require powerand rather generate a voltage in response to input forces such as sound.A display can be integrated with the sensing unit to provide directfeedback to the performance data. In one aspect, a user interface isalso integrated with the sensing unit to provide user control of thesensing unit, e.g., to include an ON/OFF switch and buttons to selectfor acquisition or display of certain performance data.

[0025] The sensing unit of one aspect is a stand-alone unit, and thusincludes a housing. The housing is rugged to survive rigorous sportingactivity. Preferably, the housing provides a universal interface whichpermits mounting of the unit to a variety of vehicle platforms, e.g.,onto a ski, snowboard, mountain bike, windsurfer, roller blades, etc.The universal interface is preferably a conformal surface whichconveniently permits mounting of the sensing unit to a plurality ofsurfaces, e.g., a flat surface such as a snowboard, and a round bar suchas on a mountain bike.

[0026] Alternatively, the sensing unit can be integrated into objectsalready associated with the sporting activity. In one aspect, thesensing unit is integrated into the ski boot or other boot. In anotheraspect, the sensing unit is integrated into the binding for a ski bootor snowboarder boot. In still another aspect, the sensing unit isintegrated into a ski, snowboard, mountain bike, windsurfer, windsurfermast, roller blade boot, skate-board, kayak, or other sport vehicle.Collectively, the sport objects such as the ski boot and the variety ofsport vehicles are denoted as “sport implements”. Accordingly, when thesensing unit is not “stand alone”, the housing which integrates thecontroller subsystem with one or more sensors and battery can be madefrom the material of the associated sport implement, in whole or inpart, such that the sensing unit becomes integral with the sportimplement. The universal interface is therefore not desired in thisaspect.

[0027] In one preferred aspect, the sensing unit provides for themeasurement of power entirely within a watch. Manufacturers such asCASIO™, TIMEX™, SEIKO™, FILA™, and SWATCH™ make sport wrist-watches withcertain digital electronics disposed therein. In accord with theinvention, power measurement capability is added within such a watch sothat “power” data can be provided to sport enthusiasts in all sports,e.g., volleyball, soccer, football, karate, and similar common sports.

[0028] In one preferred aspect, the performance data is transmitted viaradiofrequencies (or other data transfer technique, including infraredlight or inductively-coupled electronics) from the sensing unit to adata unit which is ergonomically compatible with the user. Accordingly,the sensing unit in this aspect does not require a display asperformance data is made available to the user through the data unit.For example, the data unit of one aspect is a watch that the user wearson her wrist. The data unit can alternatively be made into a“pager-like” module such as known fully in the art (MOTOROLA™ is onewell-known manufacturer that makes pager modules). In either case, thesensing unit and the data unit cooperate to provide a complete systemfor the user.

[0029] The data unit can take other forms, in other aspects. Forexample, the performance data can be transmitted directly to a radioreceiver connected to headphones worn by the user or to a small speakerworn in the user's ear. The radio receiver is for example similar to theSONY® WALKMAN®, used by plenty of sports enthusiasts. In accord withthis aspect of the invention, the sensing unit transmits performancedata directly into the receiver so that the user can listen—in realtime—to the results of his sports performance. Specifically, the radioreceiver includes a data conversion unit which responds to the receiptof performance data from the sensing unit and which converts theperformance data into sound, via the headphones, so that the userlistens to the performance data. After a jump, for example, the dataconversion unit transmits airtime and drop distance data to the user sothat the user hears “1.8 seconds of air, 5 feet drop distance”.

[0030] The data unit can also be made into the pole of a skier, suchthat a display at the end of the pole provides performance data to theuser.

[0031] In still another aspect, the data unit is not required. Rather,performance data is transmitted such as by RF directly from the sensingunit to a base station associated with the sporting area. For example,the base station can be a computer in the lodge of a ski area. Thesensing unit of this aspect transmits performance data tagged to aparticular user to the base station where performance data from allusers is collated, stored, compared and/or printed for various purposes.Preferably, the base station includes processing capability and storagewhereby performance data can be assessed and processed. For example, auser at the end of the day can receive a print-out (or computer disk) ofhis performance data; and the report can include a comparison to otherperformers within the sporting activity. If the activity issnowboarding, for example, the user can see his performance data ascompared to other snowboarders on a particular mountain. Performancedata can also be catalogued according to age, date, and performance datatype (e.g., airtime, power, speed and/or drop distance).

[0032] In one aspect, the base station augments the sensing units byproviding processing power to calculate and quantify the performancedata. For example, in this aspect, raw sensor data such as from amicrophone is transmitted from the sensing unit to the base station,which thereafter calculates the appropriate performance data. Thesensing unit “tags” the transmitted data so as to identify a particularuser. The base station of this aspect then calculates and stores theappropriate performance data for that particular user.

[0033] The base station can further include a Web Site server thatconnects the base station to other such base stations via the Internetso that performance data from users can be collated, stored, comparedand/or printed for a variety of purposes. One or more servers thusfunction as the primary servers from which users can obtain theirperformance data from their own computers, via the Internet (or via aLAN or WAN). In one aspect, the primary servers also function as agaming network where performance data from all users is integrated in arecreational manner, and made available to all or selected users.

[0034] In one aspect, sensing units (or sensing units and data units)are rented by the owners of a particular sporting area (e.g., a skiarea) such as in connection with the rental of a snowboard, or even as astand-alone device that mounts to the user's board. The sensing unit canprovide real-time performance data to the user, via a connected displayor via a data unit. Alternatively, the sensing unit transmits data tothe rental facility (or to the base station connected via a LAN to therental facility) so that the user retrieves his or her performance dataat the end of the day.

[0035] In one aspect of the invention, performance data is sensedthrough one or more sensors connected with the sensing unit. It is notdesirable to provide all performance data for all sporting activities.For example, for white water rafting or kayaking, a “power sensing unit”is useful—to quantify the roughness of the ride—but airtime data ispractically useless since typically such vehicles do not catch air. Inaddition, for any given system (i.e., sensing units or sensing units anddata units combined), more sensors add cost and require added processingcapability, requiring more power draw and reducing battery lifetime.Therefore, certain aspects of the invention provide sensing units thatprovide only that portion of the performance data that is useful and/ordesirable for a given sporting function, such as the following sensingunits:

[0036] Airtime Sensing Unit

[0037] One sensing unit of the invention measures “air” time, i.e. thetime a person such as a snowboarder or skier is off the ground during ajump. This airtime sensing unit is preferably battery-powered andincludes a microprocessor (or microcontoller). The airtime sensing uniteither connects to a data unit; or can include a low-powered liquidcrystal display (LCD) to communicate the “air” time to the user. Thecomponents for this airtime sensing unit can include one or moremicrophones or accelerometers to detect vibration (i.e., caused byfriction and scraping along the ground) of the user's vehicle along theground, so that “airtime” is measured when an appropriate absence ofvibration is detected. Preferably, the electronics for the airtimesensing unit are conveniently packaged within a single integratedcircuit such as an ASIC. A digital memory stores airtime data; oralternatively, the airtime sensing unit transmits airtime performancedata to a data unit or to a base station.

[0038] The airtime sensing unit preferably provides several facets ofairtime performance data, such as any of the following information dataand features:

[0039] (1) Total and peak air time for the day. In this aspect, theairtime sensing unit provides at least the peak airtime for the day. Thesensing unit can also integrate all airtimes for the day to provide atotal airtime.

[0040] (2) Total dead time for the day. In this aspect, the airtimesensing unit includes an internal clock that also integrates the timefor which no sporting activity is made such as over a given day. Forexample, dead time can include that time within which the user is at thebar, rather than skiing.

[0041] (3) Air time for any particular jump. As discussed above,briefly, this aspect of the airtime sensing unit provides substantiallyreal-time data to the user such as the amount of airtime for a recentjump. By way of example, a data unit with headphones, in one aspect,provide this data to the user immediately after the jump. Alternatively,the airtime data for the jump is stored within memory (either within thedata unit or in the sensing unit) so that the user can retrieve the dataat his convenience. For example, data for a particular jump can beretrieved from a watch data unit on the chairlift after a particular runwhich included at least one jump. In this manner, the user can havesubstantially real-time feedback for the airtime event.

[0042] (4) Successive jump records of air time. In this aspect, jumprecords over a selected period (e.g., one day) are stored in memoryeither in the data unit or in the airtime sensing unit. These airtime“records” are retrieved from the memory at the user's convenience. Thesystem can also store such records until the memory is full, at whichtime the oldest record is over-written to provide room for newer airtimedata. The data can also be transmitted to a base station which includesits own memory storage for retrieval by the user.

[0043] (5) Averages and totals, selectable by the user. In this aspect,the sensing unit or data unit (or the base station) saves airtime datawithin memory for later retrieval by the user. The period for which thedata is valid is preferably selectable by the user. The data of thisaspect includes airtime averages, over that period, or airtime totals,corresponding to the summation of those airtimes over that period.

[0044] (6) Rankings of records. In this aspect, the sensing unit or dataunit (or base station) saves airtime data within memory for laterretrieval by the user. For example, the user obtains airtime datathrough the data unit while on the chairlift or later obtains the datain print-out form at the base station, or a combination of the two. Theperiod for which the data is valid is preferably selectable by the user.The data of this aspect includes airtime records, over that period, andthe airtime records are preferably ranked by airtime size, the biggest“air” to the smallest.

[0045] (7) Logic to reject activities which represents false “air” time.As discussed above, the preferred airtime sensing unit includes logiccircuitry to reject false data, such as standing in line. Typically, thelogic sets outer time limits on acceptable data, such as one half secondto five seconds for snowboarding, one quarter second to three secondsfor roller-blading, and user selected limits, targeted to a particularuser's interest or activity. The logic circuitry of the airtime sensingunit preferably also works with a speed sensor, as discussed herein; andthe logic operates to measure airtime only when the sensing unit ismoving above a minimum speed. For example, when the sensing unitincludes an airtime sensor and a speed sensor, the logic ensures thatairtime data is measured only if there is motion. Such logic thenensures that false data corresponding to standing in line is notrecorded as performance data. The speed limits tied to the logic arepreferably selectable by the user; though certain default speeds are setfor certain activities. For example, for skiing and snowboarding, 5 mphis a reasonable lower speed limit, such that all airtime, drop distanceand/or power measurements are ignored at lower speeds. Forroller-blading, the lower limit of speed is reasonably 1 mph, as forwind-surfing.

[0046] (8) Toggle to other device functionality. Although this sectiondescribes an airtime sensing unit, many sensing units of the inventionincorporate at least two sensors, such as: airtime sensor and speedsensor: airtime sensor and power sensor; airtime sensor and dropdistance sensor; a combination of airtime, power, and drop distancesensors; a combination of airtime, drop distance and speed sensors; acombination of airtime, power and speed sensors; and a full sensing unitof airtime, speed, power and drop distance sensors. Accordingly, atoggle button is usually included with the sensing unit (oralternatively with the data unit) such that the user can toggle to datacorresponding to the desired performance data. Similar toggle buttonscan be included with the sensing unit or data unit (which transmits datato the sensing unit) to activate only certain portions of the sensingunit, e.g., to turn off speed sensing. Alternatively, data from anygiven sensor can be acquired according to user-specified requirements.

[0047] Those skilled in the art should appreciate that a sensing unitwith multiple sensors can simply acquire all the data, and that the datais sorted according to user needs and requests by toggle functionalityat the data unit or at the base station (i.e., such as entering arequest for the desired information at the computer keyboard).

[0048] (9) User interface to control parameters. As discussed above, thesensing unit and/or data unit preferably include buttons or toggleswitches for the user to interact with the unit. For example, one of theunits should include an ON/OFF switch, and at least one button tocommand the display of performance data.

[0049] In other aspects, the airtime data of above paragraphs (1)-(6)can be shown on a display connected with the sensing unit, or they canbe transmitted to an associated data unit, or to a base station.

[0050] Speed Sensing Unit

[0051] One sensing unit of the invention measures “speed.” This speedsensing unit is preferably battery-powered and includes a microprocessor(or microcontoller). The speed sensing unit either connects to a dataunit; or can include a low-powered liquid crystal display (LCD) tocommunicate the “speed” to the user. Certain sporting activities alsobenefit by the measurement of speed, including skiing, snowboarding,mountain biking, wind-surfing, roller-blading, and others. To detectuser motion, the sensing unit includes a speed sensor such as a Dopplermodule, as described in U.S. Pat. Nos. 5,636,146, 4,722,222, and4,757,714, incorporated herein by reference. Alternatively, the speedsensor can include a microphone subsystem that detects and bins (as afunction of frequency) certain sound spectra; and this data iscorrelated to known speed frequency data. A speed sensor can alsoinclude a microphone which, when coupled with the controller subsystem,detects a “pitch” of the vehicle; and that pitch is used to determinespeed to a defined accuracy (typically at least 5 mph). The speed sensorcan alternatively include a Faraday effect sensor (which interacts amagnetic field with an electric field to create a voltage proportionalto speed). Specifically, the Faraday effect sensor sets up a currentthat runs orthogonal to the speed direction. In one aspect, the currentis created between two electrodes formed by the two metal edges of a skior snowboard (in circuit with the snow). When the Faraday effect sensormoves, a voltage is created proportional to velocity. The magnetic fieldis formed by a magnet that creates a flux substantially perpendicular tothe current flow (those skilled in the art should appreciate that theorthogonality of the respective quantities can be compensated by a sinefunction if the quantities are not orthogonal, to retrieve the speeddata).

[0052] In another aspect, a sensing unit with a microphone, for example,can benefit by using an electrical filter with a variable bandpass thattracks the dominant spectral content, denoted herein as a “trackingfilter.”

[0053] This speed sensing unit can be stand-alone, or a speed sensor canbe integrated into a sensing unit with multiple sensors, such asdescribed above. For example, one speed sensing unit provides both “air”time and speed to the user of the device.

[0054] Preferably, the electronics for the speed sensing unit areconveniently packaged within a single integrated circuit such as anASIC. A digital memory stores speed data; or alternatively, the speedsensing unit transmits speed performance data to a data unit or to thebase station.

[0055] The speed sensing unit preferably provides several facets ofspeed performance data, such as any of the following information dataand features:

[0056] (1) Average and peak speed for the day. In this aspect, the speedsensing unit provides at least the peak speed for the day. The sensingunit can also integrate all speeds for the day to provide an averagespeed.

[0057] (2) Speed for any particular period or run. This aspect of thespeed sensing unit provides substantially real-time data to the usersuch as the speed reached in a recent run. By way of example, a dataunit with headphones can provide this data immediately (e.g.,continually informing the user of data such as “25 mph” or “15 mph”).Alternatively, the speed data for the run or period is stored withinmemory (either within the data unit or in the sensing unit) so that theuser can retrieve the data at his convenience. For example, data for aparticular run or period can be retrieved from a watch data unit on thechairlift after a particular run. In this manner, the user can havesubstantially real-time feedback for recent periods.

[0058] (3) Successive records of speed. In this aspect, peak or averagespeed records over a selected period (e.g., one day) are stored inmemory either in the data unit or in the speed sensing unit. These speed“records” are retrieved from the memory at the user's convenience. Thesystem can also store such records until the memory is full, at whichtime the oldest record is over-written to provide room for newer speeddata. The data can also be transmitted to a base station which includesits own memory storage for retrieval by the user.

[0059] (4) Averages and totals, selectable by the user. In this aspect,the sensing unit or data unit (or the base station) saves speed datawithin memory for later retrieval by the user. The period for which thedata is valid is preferably selectable by the user. The data of thisaspect preferably includes speed averages over that period.

[0060] (5) Rankings of records. In this aspect, the sensing unit or dataunit (or base station) saves speed data within memory for laterretrieval by the user. For example, the user obtains speed data throughthe data unit while on the chairlift or later obtains the data inprint-out form at the base station, or a combination of the two. Theperiod for which the data is valid is preferably selectable by the user.One record can include peak and/or average speed, over that period. Therecords are preferably ranked by velocity, the fastest to the slowestspeeds.

[0061] (6) Logic to reject data representing contaminated speed data.The preferred speed sensing unit includes logic circuitry to rejectfalse data, such as data corresponding to two hundred miles per hour.Typically, therefore, the logic sets outer speed limits on acceptabledata, such as seventy miles per hour for a skier, as an upper limit, toone or five miles per hour as a lower limit (data that is slower thanthis rate is not, generally, of interest to skiers). Other reasonablelimits are 70 mph to 5 mph for snowboarding, and 40 mph to 5 mph forroller-blading. User selected limits can also be used within the speedsensing unit and targeted to a particular user's interest or activity.

[0062] (7) Toggle to other device functionality. Although this sectiondescribes a speed sensing unit, many sensing units of the inventionincorporate at least two sensors, such as: speed sensor and powersensor; speed sensor and drop distance sensor; and a combination ofspeed, power, and drop distance sensors. Accordingly, a toggle button isusually included with the speed sensing unit (or alternatively with thedata unit) such that the user can toggle to data corresponding to thedesired performance data. Similar toggle buttons can be included withthe sensing unit or data unit (which transmits data to the sensing unit)to activate only certain portions of the sensing unit, e.g., to turn offairtime or drop distance sensing. Alternatively, data from any givensensor can be acquired according to user-specified requirements.

[0063] (8) User interface to control parameters. As discussed above, thespeed sensing unit and/or data unit preferably include buttons or toggleswitches for the user to interact with the unit. For example, one of theunits should include an ON/OFF switch, and at least one button tocommand the display of performance data.

[0064] In one aspect, a sensing unit with multiple sensors simplyacquires all the data, and that data is sorted according to user needsand requests by toggle functionality at the data unit or at the basestation (i.e., such as entering a request for the desired information atthe computer keyboard).

[0065] Power Sensing Unit

[0066] One sensing unit of the invention measures “power”, a measure ofthe amount of energy absorbed or experienced by a user during a periodsuch as a day. The power sensing unit thus provides a measure of theintensity or how “hard” the user played during a particular activity.The components for this power distance sensing unit can include one ormore microphones or accelerometers to sense vibration or “jerk” of theuser or the user's vehicle relative to the ground. For example, onepower sensing unit provides a kayaker with the ability to assess andquantify the power or forces experienced during a white-water ride. Thepower sensing unit is preferably battery-powered and includes amicroprocessor (or microcontoller). In one aspect, “power” is measuredthrough an accelerometer. In another aspect, the power sensor includes amicrophone, as discussed below. As before, the power sensing unit isstand-alone, or it can be incorporated with other units discussedherein. Preferably, the electronics for the power sensing unit areconveniently packaged within a single integrated circuit such as anASIC. A digital memory stores power data; or alternatively, the powersensing unit transmits power performance data to a data unit. One powersensor according to the invention is an accelerometer, oriented in thedirection most indicative of expended energy (e.g., for skiing, theaccelerometer is preferably oriented perpendicular to the ski surface).Another power sensor is a microphone, preferably mounted within anenclosure which generates sound in response to user activity.

[0067] The power sensing unit preferably provides several facets ofpower performance data, such as any of the following information dataand features:

[0068] (1) Peak and average power for the day. In one aspect, a powersensor is an accelerometer which generates analog data that is digitallysampled by the controller subsystem at a rate such as 1000 Hz, 100 Hz or10 Hz. This digitally sampled data is integrated over a “power period”such as one-half second, one second, five seconds, ten seconds, fifteenseconds, twenty seconds, thirty seconds, one minute, or five minutes(depending on the sporting activity)—to specify a power “value”. Inanother aspect, a peak power is determined for power values over a givenuser-selected period, e.g., one minute, one day, or other user-selectedperiod, and stored within memory (in the sensing unit, in the data unit,and/or in the base station) for subsequent retrieval by the user. Thepower sensing unit can also provide an average power value over thatperiod. By way of example, for snowboarding, a user might experiencevery high power activity over a period of fifteen seconds, such aswithin a mogul run. By determining power values over one secondintervals (i.e., the “power period”), the mogul run power activity willclearly stand out as a power event in subsequent data analysis. Thepower period can be user selected, such as over a run down a slope on amountain. For example, snowboarders over a run down a slope canintegrate power values over that period to determine a total value,which can be compared amongst users. Alternatively, the integrated valuecan be divided by the total number of samples to determine an averagepower over that run.

[0069] (2) Successive power records. In this aspect, peak power recordsare stored in memory either in the data unit or in the power sensingunit. These power “records” are retrieved from the memory at the user'sconvenience. The system can also store such records until the memory isfull, at which time the oldest record is over-written to provide roomfor newer power data. The data can also be transmitted to a base stationwhich includes its own memory storage for retrieval by the user.

[0070] (3) Rankings of records. In this aspect, the power sensing unitor data unit (or base station) saves power data within memory for laterretrieval by the user. For example, the user obtains power data throughthe data unit while on the chair-lift or later obtains the data inprint-out form at the base station, or a combination of the two. Theperiod for which the data is valid is preferably selectable by the user.The data of this aspect includes power records, over that period, andthe power records are preferably ranked by the largest to the smallest.

[0071] (4) Logic to ignore data that contaminates power data. By way ofexample, data from sensors such as accelerometers can provide noisespikes that correspond to unreasonable power values; and the logicoperates to delete such noise spikes.

[0072] (5) Toggle to other device functionality. Although this sectiondescribes a power sensing unit, many sensing units of the inventionincorporate at least two sensors, such as a power sensor and dropdistance sensor. Accordingly, a toggle button is usually included withthe sensing unit (or alternatively with the data unit) such that theuser can toggle to data corresponding to the desired performance data.Similar toggle buttons can be included with the sensing unit or dataunit (which transmits data to the sensing unit) to activate only certainportions of the sensing unit, e.g., to turn off drop distance sensing.Alternatively, data from any given sensor can be acquired according touser-specified requirements.

[0073] (6) User interface to control parameters. As discussed above, thesensing unit and/or data unit preferably include buttons or toggleswitches for the user to interact with the unit. For example, a sensingunit of one aspect includes an ON/OFF switch and at least one button tocommand the display of performance data. Since power can be scaled tocorrespond to real data, such as “g's” or “joules”, one button can beused to change the units of the power values.

[0074] Drop Distance Sensing Unit

[0075] One sensing unit of the invention measures “drop distance”. Thisdrop distance sensing unit is preferably battery-powered and includes amicroprocessor (or microcontoller). The drop distance sensing uniteither connects to a data unit; or can include a low-powered liquidcrystal display (LCD) to communicate the “drop distance” to the user.The components for a drop distance sensing unit of one aspect includes apressure sensor or altimeter. Preferably, the electronics for the dropdistance sensing unit are conveniently packaged within a singleintegrated circuit such as an ASIC. A digital memory unit stores dropdistance data; or alternatively, the drop distance sensing unittransmits drop distance performance data to a data unit.

[0076] The drop distance sensing unit preferably provides several facetsof drop distance performance data, such as any of the followinginformation data and features:

[0077] (1) Total and peak drop distance for the day. In this aspect, thedrop distance sensing unit provides at least the peak drop distance forthe day. The sensing unit can also integrate all drop distances for theday to provide a total drop distance.

[0078] (2) Drop distance for any particular jump. This aspect of thedrop distance sensing unit provides substantially real-time data to theuser such as the drop distance for a recent jump. By way of example, inone aspect, a data unit with headphones provides this data immediatelyafter the jump. Alternatively, the drop distance data for the jump isstored within memory (either within the data unit or in the sensingunit) so that the user can retrieve the data at his convenience. Forexample, data for a particular jump can be retrieved from a watch dataunit on the chairlift after a particular run which included at least onejump. In this manner, the user can have substantially real-time feedbackfor the drop distance event.

[0079] (3) Successive jump records of drop distance. In this aspect,jump records over a selected period (e.g., one day) are stored in memoryeither in the data unit or in the drop distance sensing unit (or at thebase station). These drop distance “records” are retrieved from thememory at the user's convenience. The system can also store such recordsuntil the memory is full, at which time the oldest record isover-written to provide room for newer drop distance data. The data canalso be transmitted to a base station which includes its own memorystorage for retrieval by the user.

[0080] (4) Averages and totals, selectable by the user. In this aspect,the sensing unit or data unit (or the base station) saves drop distancedata within memory for later retrieval by the user. The period for whichthe data is valid is preferably selectable by the user. The data of thisaspect includes drop distance averages, over that period, or dropdistance time totals, corresponding to the summation of those dropdistances over that period.

[0081] (5) Rankings of records. In this aspect, the sensing unit or dataunit (or base station) saves drop distance data within memory for laterretrieval by the user. For example, the user obtains drop distance datathrough the data unit while on the chair-lift or later obtains the datain print-out form at the base station, or a combination of the two. Theperiod for which the data is valid is preferably selectable by the user.The data of this aspect includes drop distance records, over thatperiod, and the drop distance records are preferably ranked by size, thelargest distance to the smallest.

[0082] (6) Logic to reject activities which represents false dropdistance. The preferred drop distance sensing unit includes logiccircuitry to reject false data. Typically, the logic sets outer dropdistance limits on acceptable data, such as three feet to one hundredfeet for snowboarding and skiing (or up to 150 feet for extreme sports),and user selected limits, targeted to a particular user's interest. Thelogic circuitry of the drop distance sensing unit preferably also workswith an airtime sensor, as discussed above; and the logic operates tomeasure drop distance only when there is a detected airtime. Forexample, when the sensing unit includes an airtime sensor and a dropdistance sensor, the logic ensures that drop distance data is measuredonly if there is an airtime event, which can include its own logic asdiscussed above. The limits for other sports varies. In roller-blading,for example, the drop distance limits can be set to one foot minimum toten or fifteen feet maximum.

[0083] (7) Toggle to other device functionality. Although this sectiondescribes a drop distance sensing unit, many sensing units of theinvention incorporate at least two sensors, such as: drop distancesensor and speed sensor; drop distance sensor and power sensor; dropdistance sensor and airtime sensor; and combinations. Accordingly, atoggle button is usually included with the sensing unit (oralternatively with the data unit) such that the user can toggle to datacorresponding to the desired performance data. Similar toggle buttonscan be included with the sensing unit or data unit (which transmits datato the sensing unit) to activate only certain portions of the sensingunit, e.g., to turn off speed sensing. Alternatively, data from anygiven sensor can be acquired according to user-specified requirements.

[0084] (8) User interface to control parameters. As discussed above, thesensing unit and/or data unit preferably include buttons or toggleswitches for the user to interact with the unit. For example, thesensing unit of one aspect includes an ON/OFF switch, and at least onebutton to command the display of performance data such as drop distance.

[0085] In one aspect, the invention incorporates a pair of power metersthat measure and quantify a competitor's performance during mogulcompetitions. In this application, one device is mounted to the ski (orlower body, such as the lower leg), and another to the upper body. An RFsignal unit communicates readings from both devices to a signalcontroller at the judge's table. The combined signals determine theforce differential between the lower legs and the upper body, giving anactual assessment of a competitor's performance. The device startstransmitting data at the starting gate. The device of this aspect canalso be coupled to the user via a data unit with headphones to provide ahum or pitch which tells the user how effective his/her approach is.

[0086] In another aspect, the invention provides a performance systemwhich gauges the negative airtime aspects of speed skiers. For example,it is undesirable for skiers such as Tommy Moe to lift off of the groundduring training, and certainly during a speed event, which slows theskier's speed. In this aspect, the system informs the user (in realtime, via a data unit) of instances of air time so that the skier canadjust and improve his competitive position. Airtime in this aspect isthus typically less than three seconds and can be as small as one tenthof a second or less. The data is preferably also communicated to a basestation so that the data can be replayed together with a video of therun, so that the skier can get feedback of airtime (unwanted in speedskiing) while watching his technique.

[0087] In another aspect, the invention provides a speed and airtimesensing unit such as described above, and additionally provides a heightsensor integrated with the sensing unit. In one aspect—identified hereinas the “default” height measure—the height sensor detects speed andconverts that speed data to height. Many jumps performed in sportingevents such as snowboarding occur off of a ledge, such that “height” isdetermined solely by the force of gravity. In one aspect, therefore,drop distance height is determined by ½ at², where a is the accelerationdue to gravity (9.81 meters per second squared, at sea level) and wheret is airtime, as determined by an airtime sensor as described herein. Byway of example, for a one second airtime, a drop distance of 4.9 metersis measured. This result is approximately true even if the airtimeoccurs on a slope down a mountain. However, this calculation will be inerror if there is an upward or downward motion at the start of theairtime. For example, if a jump occurs off of a mogul and the user islaunching upwards into the air, then this calculation will produce anincorrect number. Accordingly, the height sensor preferably includes alevel sensor which senses and measures the angle of motion relative to aplane perpendicular to the force of gravity. This angle determines thedistance which should be added or subtracted from the default measure.By way of example, if at the beginning of a two second airtime the usermoves at a speed of 10 mph (about 4.47 m/s), at an angle of 15 degreesupwards (such as off a mogul), then the velocity vector in the verticaldirection, V_(v), is sin(15°)*10 mph; and the distance added to thedefault measure is approximately sin(15°)*2(V_(v) ²)/a, or 1.05 m. Thetime for this upward-traveled distance is sin(15°)*2V_(v)/a, or 0.24s.The default time in this example is thus total airtime—0.24s; and thedefault measure is 15.2 m. The total drop distance is then 15.2 m plus1.05 m, or 16.25 m.

[0088] In one aspect, the invention provides a system for determiningthe loft time of a moving vehicle off of a surface. A loft sensor sensesa first condition that is indicative of the vehicle leaving the surface,and further senses a second condition indicative of the vehiclereturning to the surface. A controller subsystem, e.g., typicallyincluding a microprocessor or microcontroller, determines a loft timethat is based upon the first and second conditions, and the loft time ispreferably displayed to a user of the system by a display, e.g., a LCDor LED display. In another aspect, a power module such as a battery isincluded in the system to power the several components. In addition, ahousing preferably connects and protects the controller subsystem andthe user interface; and further includes an interface (possiblyincluding velcro) that facilitates attaching the housing to the vehicle.

[0089] One preferred aspect of the invention includes a speed sensor,connected to the controller subsystem, which senses a third conditionthat is indicative of a velocity of the vehicle (or at least indicatesthat the vehicle is in forward motion). In this aspect, the controllersubsystem includes means for converting the third condition toinformation representative of a speed of the vehicle. Alternatively, thespeed sensor is used as logic for the airtime sensor to switch off thecollection of data when there is no forward motion. According to oneaspect, the system provides a user with airtime and speed of thevehicle.

[0090] In yet another aspect, a display of the invention displaysselective information, including one or more of the following: the lofttime; a speed of the vehicle; a peak loft time; an average loft time; atotal loft time; a dead time; a real activity time; an average speed;successive records of loft information; successive records of speedinformation; a distance traveled by the vehicle; and a height achievedby the vehicle off of the surface.

[0091] In still another aspect, the invention includes a user interfacefor providing external inputs to the sensing and/or data units,including one or more of the following: a start/stop button forselectively starting and stopping the acquisition of data; adisplay-operate button for activating the display selectively; aspeed/loft/power/drop distance toggle button for alternativelycommanding a display of different performance data; means for commandinga display of successive records of performance data selectively; meansfor commanding a display of information corresponding to averageperformance data; means for commanding a display of dead time; means forcommanding a display of distance traveled by the vehicle upon which theuser rides; means for commanding a display of height achieved by thevehicle off of the surface; and means for commanding a display of realactivity time.

[0092] Preferably, the controller subsystem of the invention includes aclock element, e.g., a 24-hour clock, for providing informationconvertible to an elapsed time. Accordingly, the subsystem can performvarious calculations, e.g., dead time, on the data acquired for displayto a user. The clock can also be incorporated into a data unit, as amatter of design choice.

[0093] In another aspect, the airtime sensor is constructed with one ofthe following technologies: (i) an accelerometer that senses avibrational spectrum; (ii) a microphone that senses a noise spectrum;(iii) a switch that is responsive to a weight of a user of the vehicle;(iv) a voltage-resistance sensor that generates a voltage indicative ofa speed of the vehicle; and (v) a plurality of accelerometers connectedfor evaluating a speed of the vehicle.

[0094] In another aspect, induced-strain sensors, such as apiezoceramics (e.g., PZT, or lead zirconate), piezopolymer (e.g., PVDF),or shape memory (e.g., NiTiNOL) elements can be used in sensorsdiscussed herein. An “induced strain” sensor provides a measurableoutput such as a voltage in response to an applied strain, generally acompressive strain. Also, strain gages and load cells (which are usuallymade using strain gage bridges) can also be incorporated into sensorsherein: the former for measuring bending strains, the latter for forcesand compressive strains. In still another aspect, FSRs (force sensingresistors), such as those manufactured by IEE Interlink, can be used.The FSRs are pads consisting of inter-digitated electrodes over asemi-conductive polymer ink, wherein the resistance between theelectrodes decreases nonlinearly as a function of applied compressiveload, with high sensitivity and low cost.

[0095] In a preferred aspect, the airtime sensor of the invention sensesa spectrum of information, e.g., a vibrational or sound spectrum, andthe controller subsystem determines the first and second conditionsrelative to a change in the spectrum of information. Further, thecontroller subsystem interprets the change in the spectrum to determinethe loft time.

[0096] For example, one aspect of an airtime sensor according to theinvention includes one or more accelerometers that generate avibrational spectrum of the vehicle. In such an aspect, the first andsecond conditions correspond to a change in the vibrational spectrum. Byway of another example, one airtime sensor of the invention includes amicrophone subassembly that generates voltages corresponding to a noisespectrum of the vehicle; and, in this aspect, the first and secondconditions correspond to a change in the detected noise spectrum.Because these spectrums are influenced by the particular activity of auser, e.g., standing in a ski line, a controller subsystem of theinvention preferably includes logic for assessing boundary conditions ofthe spectrum and for excluding certain conditions from the determinationof airtime. Accordingly, if a skier is in a lift line, such conditionsare effectively ignored. One boundary condition, therefore, according toan aspect of the invention, includes an elapsed time between the firstcondition and the second condition that is less than approximately 500ms; such that events that are within this boundary condition areexcluded from the determination of airtime. One other boundarycondition, in another aspect, includes an elapsed time between the firstcondition and the second condition that is greater than approximatelyfive seconds; such that events that are outside this boundary conditionare excluded from the determination of airtime. Because these boundaryconditions are important in the aspects of the invention which utilize aspectrum of information, the sensing and/or data units preferablyutilize a user interface to provide selective external inputs to thecontroller subsystem and for adjusting the boundary conditionsselectively.

[0097] In one aspect, the change in a vibration or sound spectrum isdetected through waveform “enveloping” of the time domain signal, andthen by passing the output of this envelop to a threshold-measuringcircuit. Pre-filtering of the signal, especially to remove low-frequencycontent beyond high pass filtering, can also be included.

[0098] In still another aspect, the controller subsystem determines apitch of the spectrum by isolating a best-fit sine wave to a primaryfrequency of at least part of the spectrum and by correlating the pitchto a vehicle speed. Accordingly, the invention of this aspect detectsspectrum information and correlates that information to a speed of thevehicle. Typically, a higher pitch frequency corresponds to a highervehicle speed and a lower pitch frequency corresponds to a lower vehiclespeed. However, in another aspect, the selected pitch frequency iscalibrated relative to a selected vehicle and speed.

[0099] In still another aspect, speed is inferred by the amount ofenergy at different vibrational frequencies, as discussed herein.

[0100] The invention also provides, in another aspect, means for storinginformation including look-up tables with pitch-to-speed conversions fora plurality of vehicles. This is useful because different vehicles havedifferent associated noise and/or sound spectrums associated with thevehicle. Accordingly, the invention in this aspect includes memory forstoring the respective calibration information of the different vehicles(typically in a look-up table format) so that a user can utilize theinvention on different vehicles and still accurately determine speed.Specifically, a particular pitch is associated with a particular speedfor a particular vehicle; and that association is selectively made bythe user.

[0101] In several aspects of the invention, the controller subsystemincludes one or more of the following: means for selectively startingand stopping the acquisition of data by the sensing unit; means forresponding to an external request to activate a display for the displayof performance data; means for responding to an external request toalternatively display airtime, drop distance, speed and/or power; and/ormeans for responding to an external request to display successiverecords of performance data.

[0102] The invention also provides certain methodologies. For example,in one aspect, the invention provides a method for determining the lofttime of a moving vehicle off of a surface, comprising the steps of: (1)sensing the vehicle leaving the surface at a first time; (2) sensing thevehicle returning to the surface at a second time; and (3) determining aloft time from the first and second times. Preferably, the loft time isprovided to the user who performed the jump via one of the followingmethods: through a display located with the user, either in a data unitor within a sensing unit; through a real time feedback heads-up displayor headphones; through a report available at a base station located atthe area where the jump occurred, such as after a day of skiing; and/orthrough a computer linked to a network like the Internet, where theairtime data is stored on a server on the network, such as a serverlocated at the area where the jump occurred.

[0103] In still another aspect, the invention provides a method ofmeasuring the amount of “power” a user absorbs during the day. A motionsensor, e.g., a microphone or accelerometer, attaches to the vehicle,preferably pointing perpendicular to the top of the vehicle (e.g.,perpendicular to the top surface of the snowboard) so that a measure ofacceleration, “force”, jerk or jar associated with the user is made. Thedata from the motion sensor is integrated over a selected time—e.g.,over the time of the skiing day, or over power periods such as oneminute intervals—so that an integrated measure of motion is acquired. Byway of example, if the motion sensor is an accelerometer positioned witha sensitive axis arranged perpendicular to the top snowboard surface,then, through integration over the power period, an integrated measureof “power” is obtained.

[0104] Those skilled in the art should appreciate that power can beconverted to actual power or similar units—e.g., watts or joules or ergsor Newtons—though real units are not as important as having a constant,calibrated measure of “power” for each user. That is, suppose twosnowboarders have power sensors on their respective snowboards. If oneperson skis a green slope and another skis a double-diamond, then theintegrated value out of the double-diamond snowboarder will be greater.The units are therefore set to a reasonably useful value, e.g., genericpower “UNITS”. In one aspect, the power units are set such that a valueof “100” indicates a typical snowboarder who skies eight hours per dayand on maximum difficult terrain. At the same time, a snowboarder whorides nothing but green beginner slopes, all day, achieves something farless, e.g., a value of “1”. In this manner, average skiers on blue,intermediate slops will achieve intermediate values, e.g., “20” to “50”.Other scales and units are of course within the scope of the invention,and should be set to the particular activity.

[0105] Units for airtime are preferably set to seconds, such as “1.2s”.Units for speed are preferably set to miles per hour, killometers perhour, meters per second, feet per second, inches per second, orcentimeters per second. Units for drop distance are preferably set tofeet, meters, inches, or centimeters.

[0106] In one aspect, the sensing unit (and/or the data unit) has a userinterface. The interface can include a display and/or audible feedbacksuch as through headphones In one aspect, the audible feedback informsthe user of big “air” words such as “awesome” if for example asnowboarder hit really big air (e.g., over five seconds). In anotheraspect, the interface electronics include a low-power piezo “buzzer” orheadphone “bud” speaker that sounds whenever an “air” condition issensed. This provides immediate feedback to the user. Further, inanother aspect a varying pitch is used to give a speed indication. Forinstance, the ear can readily distinguish an octave pitch change, whichcan for example correspond to each 5 mph change in speed.

[0107] The measure of power according to the invention thus providessignificant usefulness in comparing how strenuous one user's activity isas compared to another. For example, suppose two users ski only blue,intermediate slopes with the exact same skill and aggressiveness exceptthat one user chooses to sit in the bar for three hours having a coupleof cocktails. At the end of an eight hour day—providing the power periodis set for the whole day—the skier who skied all eight hours will have apower measurement that is {fraction (8/5)} that of his cocktail-drinkingcompanion. They can thereafter quantitatively talk about how easy or howdifficult their ski day was. As for another example, suppose a thirdfriend skis only double-diamond slopes and he takes four hours out todrink beer. At the end of the day, his power measure may still begreater than his friends depending upon how hard he skied during hisactive time. He could therefore boast—with quantitative power data toback him up—that he had more exercise than either of his friends eventhough he was drinking half the day.

[0108] In one aspect, the invention incorporates a breathalyzer—used tomeasure a user's consumption (i.e., a blood alcohol level)—and the levelis stored such as within the memory within the controller subsystem. Abase station can upload the data to the memory, as desired.

[0109] The measure of air time, according to the invention, can also beused in a negative sense. That is, speed skiers try to maintain contactwith the ground as air time decreases their speed. By monitoring theirair time with the invention, they are better able to assess theirmaneuvers through certain terrain so as to better maintain groundcontact, thereby increasing their speed.

[0110] The measurement of air, speed and power, and drop distance, inaccord with the invention, are preferably made through one or moresensors located with the vehicle, e.g., on the snowboard or ski, uponwhich the person rides. As such, it is difficult to see the sensor; soone aspect the invention provides an RF transmitter in the sensing unit.A data unit coupled to the RF transmitter—e.g., in the form of a watch,paging unit, or radio receiver with headphones, is located at aconvenient location with the person. The performance data—e.g., air,power, drop distance and speed—is transmitted to the person forconvenient viewing, or listening. In still other aspects, a memoryelement in the data unit (or alternatively in the sensing unit) providesfor storing selected parameters such as successive records of speed,air, drop distance and power, or averages for the performance data. Datacan also be transmitted from the sensing unit to a base station, asdiscussed above. Those skilled in the art should appreciate that otherdata transfer techniques can be used instead of RF, including IR datatransfer between the units.

[0111] In one aspect, the sensing unit internally resets (i.e., shutsoff) when the unit senses no reasonable or useful performance data for apreselected period of time. By way of example, through a clock withinthe microprocessor, the unit automatic time-outs after that period,saving battery power.

[0112] In one aspect, a temperature sensor is included with the sensingunit (or data unit). A temperature profile is taken over the course of aactivity day and is later displayed so that the user may boast that heor she skied in the most arduous situations.

[0113] Preferably, performance data is accumulated and then transmittedto a base station such as a ski lodge. For mountain biking, data can betelemetered back to a club house. Through the use of Internetconnectivity, these data sets can also be downloaded off a Web site sothat the user can compare different slopes or areas, together withperformance. The data can also be evaluated and figures of merit can beapplied to each run so that a skier can look at his or her performanceand see how they did relative to other users. A skier may find forexample that he skied better on that trail than any one else all month,year or ever. A handicap can also be applied to other mountains andtrails so that a national or world competition is achieved. Thisinterconnectivity is permitted by use of the World Wide Web or simply byusing bulletin boards that are called up and updated, as known in theart. Telenet or FTP sites can also contact each other or be contacted bya home site that will assimilate the data and prepare it for display.Security could be ensured so that a user has confidence that only he orshe can access their own data.

[0114] The invention thus provides, in one aspect, a national orregional game to be played so that the many users can compare and storeperformance data. Ski areas may use this data, for example, with theparticipant's knowledge and consent so that it will lure skiers to theirlifts in the hope that they will win an award. Awards for the highestvertical drop, most air time, greatest speed or most power may also beawarded. The prizes could simply be free lift tickets.

[0115] In one aspect, power for the sensing units (or data units) may besaved during times of inactivity by powering off most of the electronicswith a solid state switch such as a MOSFET The processor or some minimumelectronics can remain powered so that when activity is detected, theremaining electronics are powered as needed. Further, to save power,sensors such as accelerometers are duty cycled.

[0116] In another aspect, downward velocity is determined by knowing therate of descent such as through a pressure sensor. Pressure sensing andairtime can thus be used to determine vertical drop, where loft isdetermined by the absence of a vibratory noise floor, for example.

[0117] In another aspect, the GPS is used to determine speed down aslope. With updates as frequent as one second, there is more than enoughbandwidth to acquire changing GPS data. GPS however can have largeerrors associated with uncertainty of positioning calculations. This maybe remedied by using differential GPS. Differential GPS makes use of afixed GPS receiver with a known position, such as at the base station.When functioning as a sensor, therefore, the GPS receiver receivesupdates from the base station to maintain accurate position. When largeerrors are received, they are rejected because the fixed receiver is ata known position, resulting in a data correction that is also applied tothe moving receiver on the slope. In some areas of the United States,the correction codes for differential GPS are broadcast for general use.

[0118] In still another aspect, when using a GPS receiver, individualski maps for each trail are downloaded into memory so that the skier maysee where they are on the display. Also, 3D topographical information isalso preferably downloaded so that features can be attached to thesemaps and to aid in performance data determination. By knowing the heightin 3D space of the receiver, and with the stored height of the slope inmemory, the distance off the ground is determined. Loft time is alsothus determined in addition to vertical drop. Loft detection with a GPSsystem may thus return the value of drop distance.

[0119] In another aspect, speed is determined by use of neural networksynthesis. A neural network extracts speed information from a sensorsuch as a microphone or an accelerometer. This is accomplished, forexample, by recording microphone data on a ski or snowboard along with atrue speed sensor, such as a Doppler microwave sensor. Two data sets arethus generated: the first data set contains data acquired from themicrophone that will be used in the final system; and the second dataset corresponds to the true device that is used as a reliable speeddetector. These two data sets are fed into a neural network, and theoutput of the neural filter is then compared with known good speed data.The various weights of the neural network are adjusted until a match isdetermined. At this point, the neural network is used to process thefirst data set to reliably determine speed. In the event that a match isnot found, a more complex but powerful network is developed. The firstdata set is then fed into the new net and a match is developed byadjusting the weights of the nodes. This process is repeated constantlyuntil a match is determined. Each failure results in a larger neuralnetwork but increases the probability that the next filter will achievea match.

[0120] In areas where the ski run is visible, the speed and trajectoryof a skier may be achieved by the use of a digital imaging system, inaccord with another aspect. The imaging system can thus include a CCDcamera that looks at the slope and watches skiers traverse down theslope. By knowing the distances along the slope, and the fact that thecamera is stationary, the distance moved is determined frame to frame,corresponding to position in time that correlates to speed. Skiers canbe identified by signs they wear, including a distinctive pattern whichallows identification of individual skiers.

[0121] The invention is next described further in connection withpreferred embodiments, and it will be apparent that various additions,subtractions, and modifications can be made by those skilled in the artwithout departing from the scope of the invention

BRIEF DESCRIPTION OF THE DRAWINGS

[0122] A more complete understanding of the invention may be obtained byreference to the drawings, in which:

[0123]FIGS. 1A and 1B show a schematic layout of a sensing unit, dataunit and base station, each constructed according to the invention, forproviding performance data to participants in sporting activities;

[0124]FIGS. 2, 3, 4 and 5 illustrative certain operational uses of theunits of FIG. 1;

[0125]FIG. 6 graphically illustrates actual vibration data taken duringa ski jump with an airtime sensor utilizing an accelerometer, in accordwith the invention;

[0126]FIGS. 6A and 6B represent processed versions of the data of FIG.6;

[0127]FIG. 7 schematically illustrates a controller subsystemconstructed according to the invention and which is suitable for use inthe sensing unit of FIG. 1;

[0128]FIG. 8 illustrates one exemplary pitch-detection process, inaccord with the invention, which is used to determine speed;

[0129]FIG. 9 schematically illustrates process methodology of convertinga plurality of acceleration values to speed, in accord with theinvention;

[0130]FIG. 10 schematically illustrates process methodology ofcalculating speed, direction, and/or vehicle drop distance, in accordwith the invention, by utilizing accelerometer-based sensors;

[0131]FIG. 11 illustrates methodology for measuring drop distance, speedand/or airtime, in accord with the invention, by utilizing a Dopplermodule as a drop distance, speed, and/or airtime sensor;

[0132]FIG. 12 illustrates an improvement to a snowboard, in accord withthe invention;

[0133]FIGS. 13 and 14 show top and side cross-sectional views,respectively, of a speed sensor of the invention, coupled to asnowboard, for determining speed by utilizing charge cookies; and FIG.15 shows a schematic diagram for processing the speed sensor of FIGS. 13and 14;

[0134]FIGS. 16 and 17 show top and side views, respectively, of anotherembodiment of a speed sensor, according to the invention, coupled to asnowboard and utilizing magnetic cookies to determine speed;

[0135]FIGS. 18 and 19 show top and side cross-sectional views,respectively, of another embodiment of a speed sensor, according to theinvention, coupled to a snowboard and utilizing optical windows todetermine speed;

[0136]FIG. 20 shows a schematic perspective view—not to scale—of a skierengaged in competition on a mogul course and of a system, constructedaccording to the invention, for monitoring two power values toquantitatively measure mogul skiing performance;

[0137]FIG. 21 schematically illustrates one system including a powersensing unit constructed according to the invention for measuringactivity energy for various sportsmen;

[0138]FIGS. 22-24 illustrate various, exemplary signals obtainablethrough the system of FIG. 21;

[0139]FIG. 25 illustrates an alternative airtime, speed and/or dropdistance measuring system, according to the invention, utilizing a GPSreceiver;

[0140]FIG. 26 schematically shows one airtime and/or power sensing unitof the invention, mounted to a snowboard;

[0141]FIG. 27 schematically illustrates a performance system utilizing adata unit in the form of a watch;

[0142]FIG. 28 illustrates a GPS-based drop distance sensing unit of theinvention;

[0143]FIG. 29 shows further detail of the unit of FIG. 28;

[0144]FIG. 30-33, 34A, 34B and 35 illustrate data collection hardwareused to reliably collect large quantities of sensor data at a remote andenvironmentally difficult location, in accord with the invention;

[0145]FIG. 36 shows a schematic view of a pressure-based drop distancesensing unit of the invention;

[0146]FIG. 37 illustrates further processing detail of the unit of FIG.36;

[0147]FIG. 38 illustrates a power watch constructed according to theinvention;

[0148]FIG. 39 shows another power watch configuration, in accord withthe invention;

[0149]FIG. 40 shows a schematic view of a power/pressure systemaccording to the invention;

[0150]FIG. 41 illustrates a two-microphone speed sensing system of theinvention;

[0151]FIG. 42 illustrates process methodology for determining dropdistance during airtime, in accord with the invention;

[0152]FIGS. 43 and 44 show real accelerometer data from a ski travelingat <2 mph and >15 mph, respectively, in accord with the invention;

[0153]FIG. 45 illustrates one system for interpreting spectral data suchas vibration to decipher airtime, power and speed, in accord with theinvention;

[0154]FIG. 46 illustrates use of a DSP to determine power in accord withthe teachings of the invention;

[0155]FIG. 47 illustrates a GPS-based system of the invention;

[0156]FIG. 48 illustrates a neural network of the invention;

[0157]FIG. 49 illustrates methodology for a two sensor speed sensingunit of the invention; and FIGS. 50-51 show representative spectra fromthe two sensors;

[0158]FIGS. 52-53 show illustrative correlation functions;

[0159]FIG. 54 illustrates a bending wave within a ski which can be usedfor power sensing, in accord with the invention;

[0160]FIG. 55 shows a two-sensor speed system constructed according tothe invention;

[0161]FIG. 56 shows a multi-sensor speed system constructed according tothe invention;

[0162]FIG. 57 shows a two-dimensional sensor speed system constructedaccording to the invention;

[0163]FIG. 58 and FIG. 59 show a Doppler-based system constructedaccording to the invention;

[0164]FIG. 60 shows a force measuring system of the invention; and FIGS.61-62 show alternative systems;

[0165]FIGS. 63-73 illustrate force sensing techniques and issues, inaccord with the invention;

[0166]FIG. 74 shows a network game constructed according to theinvention; and FIG. 75 describes further features of the game of FIG.74;

[0167]FIG. 76 shows a boot-binding sensor arrangement constructedaccording to the invention;

[0168]FIG. 77 shows a boot sensor arrangement constructed according tothe invention;

[0169]FIG. 78 illustrates data signals representative of sensing powerin accord with the invention;

[0170]FIG. 79 illustrates a Doppler sensing system constructed accordingto the invention;

[0171]FIG. 80 illustrates a watch-based sensing system constructedaccording to the invention;

[0172]FIG. 81 illustrates a clothing-integrated sensor constructedaccording to the invention;

[0173]FIG. 82 shows a flow-chart illustrating drop distance logic inaccord with the invention;

[0174]FIG. 83 shows a real-time performance system constructed accordingto the invention; and

[0175]FIGS. 84A-84H illustrate integration of a sensing unit of theinvention integrated into various implements, in accord with theinvention.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

[0176]FIG. 1A illustrates a sensing unit 10 constructed according to theinvention. A controller subsystem 12 controls the unit 10 and isconnected to one or more sensors 14 a-14 d. Typically, the subsystem 12receives data from the sensors 14 a-d through data line 16 a-d; thoughcertain sensors 14 require or permit control signals, so data lines 16a-d are preferably bi-directional. It is not necessary that the unit 10incorporate all sensors 14 a-14 d and only one of the sensors 14 a, 14b, 14 c or 14 d is required so as to provide performance data. In onepreferred embodiment, however, the unit 10 includes all four sensors 14a-14 d. In another preferred embodiment, only the airtime sensor 14 b isincluded within the unit 10.

[0177] The sensors 14 a-14 d take a variety of forms, as discussedherein. Generally, the speed sensor 14 a provides data indicative ofspeed to the controller subsystem 12 along data line 16 a. One exemplaryspeed sensor 14 a utilizes a microwave Doppler module such as made byC&K Electronics. The airtime sensor 14 b provides data indicative ofairtime to the controller subsystem 12 along data line 16 b. Oneexemplary airtime sensor 14 b utilizes a microphone such as a piezo foilby AMP Sensors, Inc. The drop distance sensor 14 c provides dataindicative of drop distance to the controller subsystem 12 along dataline 16 c. One exemplary drop distance sensor 14 c utilizes a surfacemount altimeter such as made by Sensym, Inc. The power sensor 14 dprovides data indicative of power to the controller subsystem 12 alongdata line 16 d. One exemplary power sensor 14 d utilizes anaccelerometer such as made by AMP Sensors, Inc. or Analog Devices, Inc.

[0178] In certain embodiments, one sensor 14 functions to provide datathat is sufficient for two or more sensors 14. By way of example, in oneembodiment, the airtime sensor 14 b incorporates a microphone orpiezo-foil which senses noise vibration of the unit 10. This noisevibration data is used to sense motion (and/or coarse speed) and power;and thus a single sensor 14 b functions to provide data for sensors 14 aand 14 d. Those skilled in the art should thus appreciate that thenumber of sensors 14 is variable depending upon the type of sensingtransducer and upon the processing capability of the subsystem 12 (e.g.,a DSP chip within the subsystem 12 can provide flexible processing ofdata from the sensors 14 to limit the number of sensors 14 required toprovide performance data); and that the number of sensors 14 is made forillustrative purposes.

[0179] The controller subsystem 12 preferably includes a microprocessoror microcontroller 12 a to process data from the sensors 14 and toprovide overall control of the unit 10. The microprocessor 12 a caninclude a 24 hr. clock to provide certain performance data features asdescribed herein. The subsystem 12 also preferably includes digitalmemory 12 b to store parameters used to process data from the sensors 14and to store performance data for later retrieval. The subsystem 12 alsopreferably includes logic 12 c to restrict data from the sensors 14 toreasonable data compatible with certain limits such as stored withinmemory 12 b. For example, the memory 12 b can store speed limits for thespeed sensor 14 a, and the logic 12 c operates such that any datareceived from data line 16 a is ignored if above or below a pre-setrange (typically, one to five seconds for sport activities such assnowboarding).

[0180] Those skilled in the art should appreciate that alternateconfigurations of memory 12 b and logic 12 c are possible. By way ofexample, these elements 12 b and 12 c can be incorporated entirelywithin the microprocessor 12 a; and thus the configuration of thesubsystem 12 is illustrative and not limiting. In addition, in certainembodiments of the invention as described herein, memory 12 b and/orlogic 12 c are not required, since relatively raw data is acquired bythe unit 10 and transmitted “off board” through an optional remote datatransmit section 22 (e.g., an RF transmitter) and to a data unit 50 orto a base station 70, as shown in FIG. 1B. In such embodiments, the rawdata is processed within the data unit 50 or the base station 70 so thata user of the unit 10 can obtain performance data from the data unit 50and/or base station 70.

[0181] To acquire signals from the sensors 14, the controller subsystem12 typically includes A/D converters 12 d, such as known in the art.Each sensor 14 also typically includes a preamplifier 20 which amplifiesthe signal from the transducer within the sensor 14 prior totransmission along the associated data line 16. Those skilled in the artshould however appreciate that the exact configuration of thepreamplifier 20, microprocessor 12 a and the A/D converters 12 d dependupon specifics of the sensor 14 and the subsystem 12. For example,certain sensors 14 available in the marketplace—such as an accelerometersubsystem—include pre-amplification and A/D conversion; so the data line16 and subsystem 12 associated with such a sensor should support digitaltransmission without redundant A/D conversion.

[0182] In one embodiment, the sensing unit 10 is “stand alone” and thusincludes a user interface 24 that connects to the controller subsystem12 via a data line 26. The interface 24 includes an ON/OFF switch 24 a,to manually turn the unit 100N and OFF, and one or more buttons 24 b(preferably including at least one toggle button to other unitfunctionality) to command various actions of the unit 10, e.g., thedisplay of different performance data on the display 24 c. Those skilledin the art should appreciate that the interface 24 is illustrative,rather than limiting, and that elements such as the display 24 c canreside in other areas of the unit 10. The data line 26 is preferablybi-directional so that user commands at the interface 24 are recognizedand implemented by the subsystem 12 and so that performance data storedin the memory 12 b is displayed, upon command, at the display 24 c.

[0183] A battery 30 is generally used to power the unit 10, includingthe user interface 24, controller subsystem 12 and sensors 14, if poweris required. As such, back-plane power lines 30 a are shown to connectthe battery 30 to the various elements 24, 12, 14. One preferred sensorhowever is a piezo-foil that does not require power, and thus such aconnection 30 a may not be required for a sensor with a foil (note thatthe preamplifier 20 may still require power).

[0184] The unit 10 is generally enclosed by an appropriate housing 32,such as a plastic injected molded housing known in the art. The housing32 is rugged to withstand the elements such as snow, water and dirt. Awater-tight access port 32 a permits for the removal and replacement ofthe battery 30 within the housing 32, as required, and as known in theart.

[0185] When the unit 10 is stand alone, the housing 32 also includes awindow 32 b (possibly the surface of the display 24 c integratedsubstantially flush with the housing surface) in order to see thedisplay 24 c. When stand alone, the housing 32 also includes access 32 cto the buttons 24 a, 24 b. The access 32 c is for example providedthrough pliant rubber coverings; or the buttons 24 a, 24 b are made askeypads, as known in the art, that integrate directly with the surfaceof the housing 32. Other techniques are available; and in each case thebuttons 24 b, 24 a and housing 32 cooperate so as to provide anenvironmentally secure enclosure for the electronics such as themicroprocessor 12 a while providing an operable interface to communicatewith the subsystem 12.

[0186] The housing 32 preferably includes a universal interface 32 dwhich provides flexible and conformal mounting to a variety of surfaces,such as to the relatively flat surface of a snowboard or to a round baron a mountain bike. The universal interface 32 d is designed to permitstand alone units 10 to be sold in stores regardless of how or where auser mounts the unit, to determine performance data for his or herparticular activity.

[0187] In certain aspects, the sensing unit 10 is not “stand alone.” Inparticular, it is sometimes desirable to mount the sensing unit 10 in anobscure location that is hard to see and reach, such as on a ski, orwith a binding for a ski or snowboarding boot. In such locations, it ispreferable that the unit 10 is a “black box” that is rugged to withstandabuse and environmental conditions such as water, snow and ice.Therefore, in such a configuration, the user interface 24 is notincluded within the unit 10 (since snow and dirt can cover the unit 10),but rather data from the unit 10 is communicated “off board” such as tothe data unit 50. In this configuration, a data transmit section 22receives data from the subsystem 12 via data bus 23; and transmits thedata to a remote receiver, e.g., the data receive section 56 of the dataunit 50 and/or to the data receive unit 72 of the base station 70.

[0188] The communication between unit 10 and the data unit 50, or basestation 70, is preferably via RF signals 45, known in the art, whichutilize antennas 25, 58 and 78. However, those skilled in the art shouldappreciate that other data communication techniques are available,including infrared transmission, inductively coupled data transmission,and similar remote (i.e., non-wired) techniques. The data transmitsection 22 and antennas 25, 58 and 78 are thus shown illustratively,whereas those skilled in the art should appreciate that other techniquescan replace such elements, as desired, to perform the same function.

[0189]FIG. 1B thus also shows a schematic view of a data unit 50constructed according to the invention. As mentioned above, the dataunit 50 cooperates with the unit 10 to provide performance data to auser of the unit 10. In one preferred embodiment, the unit 50 is sizedand shaped much like a portable beeper, known in the art, and caninclude a display 52 to inform the user of performance data. In anotherpreferred embodiment, the unit 50 is incorporated within a watch such asprovided by manufacturers like TIMEX™ or CASIO™. A battery 30′ providespower to the elements of the unit 50 through power lines 30 a′ (in thewatch configuration, the existing battery replaces battery 30′). A userinterface 24′ operates as described above (with like numerals) to, forexample, provide a display of performance data, upon command. The unit50 includes a housing 54 that is also preferably plastic injected moldedand rugged to protect the elements of the unit 50. Although notillustrated, the housing 54 incorporates access ports and windows, asknown in the art, to permit access to the buttons 24 b′ (preferablyincluding at least one toggle button to other unit functionality), toview the display 24 a′ (as similarly described in connection with thesensing unit 10), and/or to replace the battery 30′. The antenna 58represents one technique through which data 45 is communicated betweenthe units 10, 50; although those skilled in the art should appreciatethat other communication forms are within the scope of the invention,including communication by infrared light.

[0190] The data unit 50 generally requires a controller such as amicroprocessor 53 to control the unit 50 and the elements therein. Databuses 55 provide data interface by and between the microprocessor 53 andthe elements. Accordingly, data entered at the user interface 24′ isbidirectional through data bus 55 so that user commands are received andimplemented by the microprocessor 53. A memory 50 b is typicallyincluded within the data unit 50 (or within the processor 53) so as tostore parameters and/or performance data, much like the memory 12 b.

[0191] In a preferred embodiment, performance data is thus madeavailable to a user via the display 52. However, in another embodiment,performance data is transmitted to a headphones assembly 60 connected,datawise, to the microprocessor 53 so that performance data is relayedin near real time, as the user performs the associated stunt. Theheadphones 60 connect to the unit 50 by standard wiring 62 and into ajack 64 in the unit 50. For example, through the user interface 24′, theuser can command the microprocessor 53 to provide airtime data to theheadphones 60 immediately after an airtime is detected. Otherperformance data can similarly be set, such as continual speed playback,through the headphones 60.

[0192] Performance data can thus be viewed on the display 52 and/or“heard” with the headphones assembly 60. In either case, a user commandsthe unit 50 to provide performance data for any memory stored withinmemory 12 b or 50 b. Accordingly, data communication between the units10 and 50 is preferably bi-directional, so that a user's command atinterface 24′ is understood and implemented by the processor 12 a.

[0193] Those skilled in the art should appreciate that themicroprocessor 53 need not be a complex or expensive microprocessor asthe majority of the processing for performance data is done within thesensing unit 10. As such, the microprocessor 53 can be a microcontrollerwhich operates with basic functionality, e.g., to display performancedata corresponding to user inputs at the interface 24′. How processingis apportioned between the units 50, 10 is, however, a matter of designchoice. That is, for example, most of the processing can be done withinthe unit 50, wherein the unit 10 can then have reduced processingcapability, if desired. These choices extend to elements such as thememories 12 b, 50 b, as they can have redundant capability. When theunit 10 is stand alone, a user interface 24 is generally included(unless data is transmitted directly to the base station 70 for laterretrieval). When the system of the invention includes both units 10, 50,then the user interface 24 is generally not included since the interface24′ sufficiently controls the system. In this latter case, thefunctionality and configuration of the microprocessors 12 a, 53, memory12 b,50 b and logic 12 c are a matter of design choice; and someelements might be eliminated to save cost. For example, the memory 50 bcan be designed to support all memory requirements of a systemincorporating both units 10, 50 to eliminate redundancy; and thus memory12 b would not be required.

[0194] Other configurations of a system combining units 10 and 50 exist.For example, one configuration eliminates the display 52 so thatperformance data is only available via the headphones assembly 60. Inanother configuration, the sensing unit 10 works only with the basestation 70 and without a data unit 50. Further, such a configurationneed not include a user interface 24 or a display 24 c, since all datacollected by the unit 10 can be stored and processed at the base station70.

[0195] The base station 70 thus includes an antenna 78 and a datareceive unit 72 (or alternatively other wireless communicationtechnology, as known in the art) to collect data signals 45. Typically,the base station 70 corresponds to a well known facility located at thesporting area, such as a ski lodge. A base station computer 74 connectsto the base station data receiver unit 72, via the bus 76, to collectand process data. As such, one sensing unit 10 of the invention simplyincludes one or more sensors 14 and enough control logic and processingcapability to transmit data signals 45 to the base station 70, so thatsubstantially all processing is done at the base station 70. Thisconfiguration is particularly useful for aspects of the invention suchas speed skiing, where the sensing unit 10 is mounted with the speedskier's ski, but where that user has no requirement to view the datauntil later, after the run (or where instructors or judges primarily usethe data). However, as discussed above, that speed skier can also use adata unit 50 with headphones 60 to acquire a real-time feedback ofunwanted airtime, such as through an audible sound, so as to correct hisor her form while skiing. In one aspect, the base station 70 preferablyhas the capability to collect, analyze and store performance data on aserver 82 for later review.

[0196] Accordingly, the base station 70 includes a computer 74 tocollect, analyze and process data signals to provide performance data tousers and individuals at the base station 70. The performance data isgenerally stored on a server 82, which can have an Internet connection84 so that performance data can be collected from remote locations. Ifthere are multiple users, which typically is the case, then the sensingunit 10 associated with each user “ags” the data with a code identifyinga particular person or unit 10, such as known in the art. The server 82then stores performance data tagged to a particular individual or unitso that the correct information is provided, upon request (such asthrough the Internet or through the computer 74). Performance data canalso be printed through printer 86 for users and persons at the basestation 70.

[0197] Although the base station 70 can be configured to processsubstantially raw data signals from units 10 (and particularly from thesensors 14), the base station typically collects performance datadirectly from the sensing unit 10 for each of a plurality of users andstores all the data, tagged to the particular user, in the server 82.The stored data can then reviewed as required. By way of example, avideo station 90 can be included with the base station 70 and users,instructors or judges can review the performance data in conjunctionwith video data collected during the run by known video systems (ortelevision systems).

[0198] With further reference to FIGS. 1A and 1B, the displays 24 c, 52can be one of any assortment of displays known to those skilled in theart. For example, liquid crystal displays (LCDs) are preferred becauseof their low power consumption (for example, LCDs utilized in digitalwatches, portable computers and paging units are appropriate for usewith the invention). Other suitable displays can include an array oflight emitting diodes (LEDs) arranged to display numbers.

[0199] The headphones assembly 60 can also be replaced with a heads-updisplay unit, known in the art, such as described in connection withU.S. Pat. No. 5,162,828, incorporated herein by reference.

[0200] As illustrated in FIG. 2, the invention in one embodimentoperates as follows. The sensing unit 10′ is mounted via its housing 32to a sporting vehicle, such as a snowboard or mountain bike, or such asthe ski 102 of FIG. 2. As illustrated, the skier 100 is catching airduring a jump off the ground 103. The skier 100 can obtain instantaneousairtime data via headphones 60′, discussed above, or he can laterretrieve the airtime data through a data unit 50′ (shown illustrativelyon the skier's jacket 100 a when typically the unit 50′ would be withina pocket or connected to a belt of the skier 100) or at a base station70′ (FIG. 1B).

[0201]FIG. 3 shows another typical use of the unit 10 of FIG. 1A. Inparticular, FIG. 3 shows the sensing unit 10 mounted onto a ski 126. Asis normal, the ski 126 is mounted to a skier 128 (for illustrativepurposes, the skier 128 is only partially illustrated), via a ski boot130 and binding 130 a, and generally descends down a ski slope 132 witha velocity 134. Accordingly, one use of a unit 10 with a speed sensor isto calculate the peak speed of the ski 126 (and hence the skier 128)over a selectable period of time, e.g., during the time of descent downthe slope 132. However, the unit 10 also provides information such asdrop distance, airtime and power, as described herein, provided theassociated sensors are included with the unit 10.

[0202] Another use of the unit 10 of FIG. 1A is to calculate the airtimeof a vehicle such as the ski 126 (and hence the user 128) during thedescent down the slope 132. Consider, for example, FIG. 4, whichillustrates the positions of the ski 126′ and skier 128′ during alofting maneuver on the slope 132′. The ski 126′ and skier 128′ speeddown the slope 132′ and launch into the air 136 at position “a,” andlater land at position “b” in accord with the well-known Newtonian lawsof physics. With an airtime sensor, described above, the unit 10calculates and stores the total airtime that the ski 126′ (and hence theskier 128′) experiences between the positions “a” and “b” so that theskier 128′ can access and assess the “air” time information.

[0203]FIG. 5 illustrates a sensing unit 10″ mounted onto a mountain bike138. FIG. 5 also shows the mountain bike 138 in various positions duringmovement along a mountain bike race course 140 (for illustrativepurposes, the bike 138 is shown without a rider). At one location “c” onthe race course 140, the bike 138 hits a dirt mound 142 and catapultsinto the air 144. The bike 138 thereafter lands at location “d”. Asabove, with speed and airtime sensors, the unit 10 provides informationto a rider of the bike 138 about the speed attained during the ridearound the race course 140; as well as information about the airtimebetween location “c” and “d”.

[0204] Airtime sensors such as the sensor 14 b of FIG. 1A may beconstructed with known components. Preferably, the sensor 14 bincorporates either an accelerometer or a microphone. Alternatively, thesensor 14 b may be constructed as a mechanical switch that detects thepresence and absence of weight onto the switch. Other airtime sensors 14b will become apparent in the description which follows. For background,consider U.S. Pat. No. 5,636,146.

[0205] An accelerometer, well known to those skilled in the art, detectsacceleration and provides a voltage output that is proportional todetected acceleration. Accordingly, the accelerometer sensesvibration—particularly the vibration of a vehicle such as a ski ormountain bike—moving along a surface, e.g., a ski slope or mountain biketrail. This voltage output provides an acceleration spectrum over time;and information about airtime can be ascertained by performingcalculations on that spectrum. Specifically, the controller subsystem 12of FIG. 1A stores the spectrum into memory 12 b and processes thespectrum information to determine airtime.

[0206]FIG. 6 shows a graph 170 of an actual vibrational spectrum 172acquired by an airtime sensor 14 b (utilizing an accelerometer) during aski jump and stored in memory 12 b, in accord with the invention. Theairtime sensing unit was mounted to a ski boot which in turn was mountedwith a ski binding. The sensitive axis of the accelerometer was orientedsubstantially vertical to the flat portion of the ski surface. Thevertical axis 174 of the graph 170 represents voltage; while thehorizontal axis 176 represents time. At the beginning of activity177—such as when a user of the sensing unit 10 presses the start/stopbutton 24 a—the airtime sensor 14 b began acquiring data andtransferring that data to the controller subsystem 12 via communicationlines 16 b. The initial data appears highly noisy and random,corresponding to the randomness of the surface underneath the vehicle(i.e., the ski). At time “t₁” the skier launched into the air, such asillustrated as location “a” in FIG. 4; and he landed at time “t₂,” suchas illustrated as location “b” in FIG. 4. The vibrational spectrum 172between t₁ and t₂ is comparatively smooth as compared to the spectrumoutside this region because the user's vehicle—i.e., the ski boot—was inthe air and was not therefore subjected to the random vibrations of theski slope (i.e., vibrations which travel through the binding, throughthe boot and into the sensing unit). Accordingly, the relatively smoothspectrum between t₁ and t₂ is readily discerned from the rest of thespectrum by the controller subsystem 12 and evaluated for airtime;specifically, airtime is t₂-t_(i).

[0207]FIG. 6 also shows that the spectrum stops at the end 178 of thesporting activity, when the controller subsystem stopped taking data(such as in response to an ON/OFF toggle on switch 24 a).

[0208] Typical accelerometer taken from a skier going down a hill isthus shown in FIG. 6. In order to determine power, or shock, in oneaspect, the data is accumulated by taking the absolute value andintegrating that data. FIG. 6A graphically shows the result ofintegrating the data of FIG. 6.

[0209] Another method of the invention for determining a measure ofpower associated with stored accelerometer data is to perform a FastFourier Transform on the data and to integrate the magnitude to find thetotal energy associated therewith. In the plot of FIG. 6B, the data fromFIG. 6 was transformed with an FFT routine, and then converted toabsolute value, point by point, and integrated, providing one measure ofenergy.

[0210] The data of FIG. 6 can also be reduced to a single number such asvia a root-mean-square of the data. This is done by squaring each sampleof the data and then summing. The resultant integration can then bedivided by the duration of the data acquisition run, giving a mean, withthe resulting number rooted. In the case of the FIG. 6, that wouldprovide a value 4.0

[0211] A microphone, also well known to those skilled in the art,detects sound waves and provides a voltage output that is responsive todetected sound waves. Accordingly, a microphone, like the accelerometer,mounted to the vehicle senses the vibration of a vehicle, such as a skior mountain bike, moving along a surface, e.g., a ski slope or mountainbike trail. By way of analogy, consider putting one's ear flat onto adesk and running an object across the desk. As one can readilydetermine, the movement of the object on the desk is readily heard inthe ear. Likewise, a microphone within an airtime sensor 14 b readily“hears” the vibrational movements of the vehicle on the surface.Therefore, like the aforementioned accelerometer, a vibrational spectrumsuch as shown in FIG. 6 is generated by a microphone-based airtimesensor during a user's sporting activity. As above, the controllersubsystem 12 utilizes this spectrum to determine airtime.

[0212] A microphone is preferably coupled with a coupling layer ofmaterial that matches the impedance for the propagation of compressionwaves (commonly referred to as “sound waves” when in air) between theimpedance of the vehicle, e.g., the ski or board, and the microphonetransducer, thus transmitting the most “sound” power to the sensor. This“matching layer” of intermediate impedance is commonly used in sonar, asknown in the art, and it is easily applied, such as with glue.

[0213] The airtime sensor 14 b of FIG. 1A can also incorporate a switchthat rests below the boot of the ski. Through the switch, the airtimesensor senses pressure caused by the weight of the user within the boot.That is, when the skier is on the ground, the boot squeezes the switch,thereby closing the switch. The closed switch is detected by thecontroller subsystem 12, FIG. 1A, as a discrete input. When a skierjumps into the air, for example, the switch opens up by virtue of thefact that relatively no weight is on the switch; and this opened switchis also detected and input into controller subsystem 12. The controllersubsystem 12 counts at known time intervals (clock rates) for theduration of the opened switch, corresponding to the jump, to determineairtime.

[0214] Another airtime sensor 14 b of the invention changes capacitanceas a function of a change of applied pressure. For example, a materialbeneath the boot that changes capacitance under varying appliedpressures can be used for this airtime sensor. The change in capacitanceis converted to a digital signal by conditioning electronics within thecontroller subsystem 12 to determine airtime.

[0215] The controller subsystem of the invention is constructed withknown components, such as shown in FIG. 7, which illustrates analternative configuration to the subsystem 12 of FIG. 1A. Specifically,FIG. 7 shows controller subsystem 150 constructed according to theinvention and including a Central Processing Unit (CPU) 152, memory 154,interface electronics 156, and conditioning electronics 158. The userinterface 160, such as the interface 24 of FIG. 1A, and including thebutton inputs 24 b, connects to the subsystem 150 such as shown anddirectly to the conditioning electronics 158. The display 162, such asthe display 24 c of FIG. 1A, preferably connects to the subsystem 150such as shown and directly to the CPU 152.

[0216] The CPU 152 includes a microprocessor 152 a, Read Only Memory(ROM) 152 b (used to store instructions that the processor may fetch inexecuting its program), Random Access Memory (RAM) 152 c (used by theprocessor to store temporary information such as return addresses forsubroutines and variables and constant values defined in a processorprogram), and a master clock 152 d. The microprocessor 152 a iscontrolled by the master clock 152 d that provides a master timingsignal used to sequence the microprocessor 152 a through its internalstates in its execution of each processed instruction. The clock 152 dis the master time source through which time may be deduced in measuringvelocity or air time (for example, to determine the elapsed time fromone event to another, such as the lapsed time “t₁” to “t₂” of FIG. 6,the clock rate provides a direct measure of time lapse).

[0217] The microprocessor subsystem 150, and especially the CPU 152, arepreferably low power devices, such as CMOS; as is the necessary logicused to implement the processor design.

[0218] The subsystem 150 stores information about the user's activity inmemory. This memory may be external to the CPU 152, such as shown asmemory 154, but preferably resides in the RAM 152 c. The memory may benonvolatile such as battery backed RAM or Electrically ErasableProgrammable Read Only Memory (EEPROM). Sensor inputs 164 from thevarious sensors 14 are connected to the conditioning electronics 158which filters, scales, and, in some cases, senses the presence ofcertain conditions, such as zero crossings. This conditioningessentially cleans the signal up for processing by the CPU 152 and insome cases preprocesses the information. These signals are then passedto the interface electronics 156, which converts (by A/D) the analogvoltage or currents to binary ones and zeroes understood by the CPU 152.

[0219] The invention also provides for intelligence in the signalprocessing, such as achieved by the CPU 152 in evaluating historicaldata. For example, airtime may be determined by the noise spectra thatchanges abruptly, such as indicating a leap, instead of a noise spectrarepresenting a more gradual change that would occur for example when askier slows to a stop. As previously noted, a minimum quiet time isrequired, in certain embodiments of the invention, to differentiatebetween airtime and the natural motions associated with turning andskiing (e.g., jump skiing). Further, in other certain embodiments, amaximum time is also programmed to differentiate airtime from an abruptstop, such as standing in a lift line.

[0220] In accord with the invention, if speed is calculated within thesensing unit 10, FIG. 1A, then the speed sensor 14 a can incorporate oneor more of the following: (1) a pitch detection system that detects the“pitch” of the vibrational spectrum and that converts the pitch to anequivalent speed; (2) a laser-based, RF-based, or sound-based Dopplermodule; (3) accelerometers or microphones; (4) pressure transducers; (5)voltage-resistance transducers; and (6) a DSP subsystem that quantifiesand bins accelerometer or sound data according to frequency. Other speedsensors 14 a will become apparent in the description which follows. Forbackground, consider U.S. Pat. No. 5,636,146.

[0221] As described above, detection of airtime is facilitated bydetecting motion, which is less difficult that determining speed. Theabove speed sensors are thus also suitable as “motion” detect sensorsthat assist the controller subsystem 12 to logic out unwanted data,e.g., airtime data when standing in line.

[0222] In accord with one embodiment, a vibrational spectrum is obtainedthrough an airtime sensor with an accelerometer or microphoneembodiment; and this spectrum is analyzed by the controller subsystem todetermine the pitch of the vibration and, thereby, the equivalent speed.By way of example, note that a skier generates a scraping sound onhard-packed snow and ice. When the skier changes velocity, that scrapingsound changes in pitch (or in volume). By calibrating the subsystem 12to associate one pitch (or volume) as one velocity, and so on, the speedof the vehicle (e.g., ski and mountain bike) is determined by spectralcontent. One technique for determining the “pitch” of the spectrum is todetermine the best fit sine wave to the vibrational spectrum data. Thissine wave has a frequency, or “pitch” that may be quantified and used tocorrelate velocity. The spectrum can also be sampled and “binned”according to frequency, as discussed below, to determine changes involume at select frequencies (or ranges of frequencies) which providespeed correlation.

[0223] Spectral content may be determined, at least in part, by theconditioning electronics 158 of FIG. 7. The electronics can also assessthe rise times to infer a bandwidth of the information. The conditioningelectronics 158 and/or CPU 152 can also measure the time betweensuccessive zero crossings, which also determines spectral content.

[0224] For example, FIG. 8 illustrates a spectrum 166 generated fromcombination speed and airtime sensor 14 a, 14 b in the form of anaccelerometer or microphone. The spectrum 166 thus represents anacceleration spectrum or sound spectrum such as described herein. Thecontroller subsystem 12 of FIG. 1A evaluates the spectrum 166 andgenerates a best-fit sine wave 167 to match the primary frequency of thespectrum 166 over time. FIG. 8 shows illustratively a situation where avehicle, such as a ski, moves slowly at first, corresponding to a lowersine-wave frequency, then faster, corresponding to a higher frequencysine wave, and then slower again. This pitch transition is interpretedby the controller subsystem as a change of speed. Specifically, thecontroller subsystem has calibration data to associate a certainfrequency with a certain speed, for the given vehicle; and speed is thusknown for the variety of pitches observed during an activity, such asillustrated in FIG. 8.

[0225] Variations in the character of the snow, and other environmentalfactors such as sun exposure, and user altitude, can also be factored inspeed sensing, in another asepct. Further, speed spectra likely variesdepending on the characteristic spatial scale(s) of the ground, e.g.,the snow for a fixed skier speed. These spatial scales are set by thetemperature at which the snow was deposited, thawing and refreezingcycles, and the sun exposure even within a day.

[0226] It should be noted that pitch information (or volume data) issurface dependent (and vehicle dependent). For example, aski-over-snow-speed-spectrum has a different spectrum than abicycle-over-ground-spectrum. Accordingly, different calibrations shouldbe made for different vehicles and speeds, in accord with the invention.Further, certain spectrums may actually decrease in frequency as speedincreases, which should be calibrated to obtain correct speedinformation. These calibrations are typically programmed into thecontroller subsystem memory, e.g., the memory 12 b of subsystem 12 ofFIG. 1A. Further, in certain embodiments of the invention, the sensingunit (or data unit or base station, as appropriate) stores differentspectrum calibrations for different activities so that a user can movethe sensing unit from one sport to another. Accordingly, one or morebuttons such as the buttons 24 b are used to selectively access thedifferent spectrum calibrations.

[0227] It is well known that Doppler radar is used by police vehicles todetect speed; and a speed sensor incorporating a Doppler module can beused to determine speed. U.S. Pat. Nos. 5,636,146, 4,722,222 and4,757,714 provide useful background.

[0228]FIG. 9 schematically illustrates process methodology, according tothe invention, which converts a plurality of acceleration inputs tospeed. For example, when a plurality of six accelerometers are connectedto a controller subsystem, the process methodology of the invention ispreferably shown in FIG. 9. Specifically, six accelerometers areconnected with various sensitive orientations within a speed sensingunit 14 a to collect pitch 207 a, yaw 207 b, roll 207 c, surge 207 d,heave 207 e, and sway 207 f accelerations. These accelerations areconditioned by the conditioning electronics 158′ through the interfaceelectronics 156′ and CPU 152′ to calculate speed, such as known to thoseskilled in the art of navigational engineering (for example, GyroscopicTheory, Design, and Instrumentation by Wrigley et al., MIT Press (1969);Handbook of Measurement and Control by Herceg et al, SchaevitzEngineering, Pensauker, N.J., Library of Congress 76-24971 (1976); andInertial Navigation Systems by Broxmeyer, McGraw-Hill (1964) describesuch calculations and are hereby incorporated herein by reference). Theelements 158′, 156′ and 152′ are similar in construction to the elements158, 156 and 152 described in connection with FIG. 7.

[0229]FIG. 10 schematically illustrates further process methodologiesaccording to the invention wherein the six acceleration inputs 207 a-207f are processed by a controller subsystem of the invention (e.g.,subsystem 12 of FIG. 1A) such that centripetal, gravitational, and earthrate compensations are performed so that the various accelerations areproperly integrated and compensated to derive speed (and even directionand distance). Specifically, a controller subsystem of the FIG. 10embodiment includes a centripetal acceleration compensation section 208a which compensates for motions of centripetal accelerations via inputsof surge 207 d, heave 207 e, and sway 207 f. A gravity accelerationcompensation section 208 b in the subsystem further processes theseinputs 207 d-207 f to compensate for the acceleration of gravity, whilea earth rate compensation section 208 c thereafter compensates for theaccelerations induced by the earth's rotation (e.g., the earth rateacceleration at the equator is approximately opposite in direction tothe force of gravity).

[0230] Also shown in FIG. 10 are translational integrators 209 a-209 cwhich convert the compensated accelerations from inputs 207 d-207 f totranslational velocities by integration. Integrators 210 a-210 clikewise integrate inputs of pitch 207 a, yaw 207 b, and roll 207 c toangular velocity while integrators 211 a-211 c provide a furtherintegration to convert the angular velocities to angular position. Theangular positional information and translational velocity information iscombined and processed at the speed and direction resolution section 212to derive speed and direction. Preferably, the subsystem with thecomponents 208, 209, 210, 211 and 212 is calibrated prior to use; andsuch calibration includes a calibration to true North (for a calibrationof earth rate).

[0231] It should be noted that fewer of the inputs 207 a-207 f may beused in accord with the invention. For example, certain of the inputs207 a-207 f can be removed with the section 208 a so that centripetalacceleration is not compensated for. This results in an error in thecalculated speed and direction; but this error is probably small so thereduced functionality is worth the space saved by the removed elements.However, with the increased functionality of the several inputs 207a-207 f, it is possible to calculate drop distance in addition to speedbecause distance in three axes is known. Therefore, the inventionfurther provides, in one embodiment, information for displaying dropdistance achieved during any given airtime, as described above.

[0232] As used herein, “cookie” measurements refer to one technique ofthe invention for measuring speed. In this method, for example, thespeed sensor drops a measurable entity—e.g., electronic charge—into thesnow and then picks it up later at a known distance away to determinethe speed. The “charge” in this example is the “cookie.”

[0233] In skiing, for example, this method involves dropping a cookie asthe ski travels and then detecting the cookie at a known distance downthe length of the ski. The time between placement and detection given aknown length between the two occurrences determines the speed. A cookietherefore represents the placement of some measurable characteristic inthe snow underneath. This characteristic may be electrical charge,magnetic moments, a detectable material such as ink, perfume,fluorescent dye or a radiation source. The cookies may be dropped at aconstant rate, i.e. cookies per second, or at a fixed distance betweencookies. In such cases the cookies are said to be dropped in a closedloop fashion. Also the amount of charge, magnetic moment, or detectablematerial may be controlled so that the detection occurs just abovethreshold. This tends to minimize the amount of electrical power usedand to minimize the amount of material dispensed. In one aspect, thecookies correspond to dots of dye that are dropped at regularly spacedintervals and which glow when irradiated with a pumping light spectrum,for example a UV pump to drive fluorescence response in blue/blue-green,or a red pump to drive fluorescence in the IR.

[0234] In FIGS. 13 and 14, a snowboard 498 traveling in a direction 504has two sets of electrodes attached to the ski. The first electrode set503 is used to charge a small amount of snow 499 by applying an electricpotential across terminals 501 a and 501 b. The potential in that snow499 is then read by the second set of electrodes 502, accomplished bysampling the potential between terminals 500 a and 500 b.

[0235] Since the level of charge in the snow 499 is quite low, aninstrumentation amplifier may be used to condition the signal, such asknown to those skilled in the art. FIG. 15 shows the charge anddetection loop according to one preferred embodiment. A potential source(e.g., a battery such as battery 30, FIG. 1A) with an electrode set 503are used to charge the first electrodes 501 a, 501 b. When the output ofthe instrumentation amplifier 501 is above a predetermined threshold,the control and timing circuit 505 triggers a flip-flop (not shown) thatnotifies the controller subsysetm 12, FIG. 1A, that the charge isdetected. The time that transpired between placing the charge at 503 todetecting the charge at 502 is used to determine speed. The speed is thedistance between the two sets of electrodes 503 to 502 divided by thetime between setting and receiving the charge. The functionality of thetiming and control circuit 505 can be separate or, alternatively, can beintegrated with the controller subsystem such as described herein.

[0236] The second set of electrodes 502 that is used to detect thecharge may also be used to clear the charge such as by driving a reversevoltage (from the control and timing circuit 505 and through directcircuitry to the electrodes 502). In this manner to total chargeresulting from the ski traversing the field of snow will be zero so thatthere will be no charge pollution. Also it will not confuse another skispeed detection system according to the invention.

[0237] In summary, the speed sensor of FIGS. 13-15 thus include twoelectrode pairs, 503, 502.

[0238] The situation described above is also applicable to magneticmoment cookies. In FIGS. 16 and 17, for example, a snowboard 507 showntraveling in a direction 512 has an electromagnet 511 mounted on top ofthe snowboard 507 and a magnetic sensor 510 at a rearward position. Asthe snowboarder skis along direction 512 the electromagnet 511 impressesa magnetic moment into the snow and water that resides under thesnowboard 507. This is done by asserting a strong magnetic field fromthe electromagnet 511 and through the snowboard 507 for a short periodof time. This polarization is then detected by the magnetic sensor 510.The period of time it takes from creating the magnetic moment at 511 todetecting it at 510 is used in determining the speed of the snowboard507 (such as through control and timing circuitry described inconnection with FIG. 15). The magnetic sensor 510 may also be used tocancel the magnetic moment so that the total magnetic moment will bezero after the ski travels from placement through detection and removal.

[0239] Those skilled in the art should appreciate that the elements 510,511 are shown grossly separated, for purposes of illustration. Placingthe elements closer (and preferably within the same housing 32, FIG. 1A)increases the required response time of the controller subsystem, thoughit decreases the amount of power required to detect the signal (sincethe cookie signal is stronger over a shorter period).

[0240] A similar speed sensing system is shown in FIGS. 18 and 19.Specifically, the speed sensor of FIG. 18 includes an opticalcorrelation subsystem with a laser source and receiver contained inpackage 522. The laser is directed through two windows 520 and 521within a snowboard 530. The laser backscatter is cross correlated overtime between the two windows 520, 521. This means that the two timesignals are multiplied and integrated over all time with a fixed timedelay between the two signals. The time delay between the twobackscatter signals that yields the highest cross correlation is theperiod of time the snowboard takes to travel the distance of the twowindows 520, 521. The speed of the snowboard 530 along direction 523 isdetermined by knowing the window separation distance. The source doesnot have to be a laser but can be noncoherent visible light, infrared orany high frequency electromagnetic radiation source.

[0241] One drop distance sensor 14 c of the invention utilizes analtimeter such as manufactured by Sensym, Inc. The altimeter iscalibrated relative to height variations and the sensing unit 10thereafter monitors pressure change to assess drop distance.Accordingly, in the preferred embodiment, such a drop distance sensoroperates with an airtime sensor 14 b since drop distance is generallyonly meaningful in connection with a jump. When the sensing unit 10detects an airtime, the same period is evaluated through the altimeterto determine drop distance over that period. Accordingly, altimeter datashould be stored in the memory 12 b (or alternatively in the memory 50b, or in the base station 70) for at least the period of the longestexpected airtime (e.g., greater than five seconds for snowboarding, orgreater than the period set by the user).

[0242] Drop distance can also be determined through a drop distancesensor that includes a plurality of accelerometers, such as shown inFIGS. 9 and 10. Through integration of appropriate acceleration vectorsindicative of a user's movement perpendicular to the ground, dropdistance is determined. A double integration of accelerometers in thedirection perpendicular to ground (or thereabouts) during an airtimeperiod provides the correct signals to determine skier height.

[0243] It should be apparent to those in the art that the accelerometersof FIGS. 9 and 10 provide sufficiently detailed information such thatthe entire sensing unit can be mounted to a user of the system directly,rather than onto a vehicle. With the scope of the compensationsdescribed in connection with FIG. 10, for example, movements of thehuman body, e.g., centripetal motions, may be compensated for to derivespeed and/or airtime information that is uncorrupted by the user'smovements. Such compensations, however, require powerful processingcapability.

[0244] Other features can also be determined in accord with theinvention such as through measurements with the system of FIG. 10. Forexample, once you know your starting velocity, you can measure distancetraveled and height above the ground by knowing the air time for a givenjump. Other ways of doing this are by using accelerometers to integratethe height distance. The preferred way of determining distance is toknow your velocity at the jump start location, such as described herein,and to use the airtime to establish a distance traveled, since distanceis equal to velocity times time (or airtime).

[0245] For height, a sensing unit of the invention also determinesheight by looking at the time to reach the ground during an airtime.That is, once in the air, you are accelerating towards the ground at9.81 meters per second{circumflex over ( )}2 (at sea level). The sensingunit thus first determines the time for which there is no more upwardsmovement (such as by using an accelerometer or level sensor that knowsgravity direction and which changes directions at the peak, or by usingcircuitry which establishes this movement, or by determining the angleimmediately prior to launch to quantify a bias distance or time to adefault measure), and then calculate the distance traveled (in height)by knowing that the default measure is equal to ½a t{circumflex over( )}2, where a is the acceleration of gravity (9.81 m/s{circumflex over( )}2) and t is the airtime after the peak height is reached. If theperson does not travel upwards or downwards at the start of a jump, thenthe height is simply ½ at{circumflex over ( )}2 where t is the entireairtime.

[0246] A Doppler module can additionally provide height information; andthus a Doppler module can function as both a speed sensor 14 a and adrop distance sensor 14 c. Further, since the impedance changes when avehicle to which the Doppler module leaves the ground, the Dopplermodule can further function as an airtime sensor 14 b. By sweeping thefrequency through various frequencies, as known in the art, the signalfrequency mix can be monitored to determine altitude relative to thedirection of the antenna lobes (typically such Doppler systems are usedas microwave ranging systems). Preferably, therefore, there are twoantennas: one to perform Doppler speed, with high spatial accuracy inthe antenna lobe so that speed is achieved, and another antenna toprovide a lobe that roughly covers the ground area in about a 60 degreecone under the user so as to achieve first-return distance measurement.With reference to FIG. 11, a Doppler module 248 functions as the dropdistance sensor and resides within a sensing unit 250 mounted to asnowboard 252 (shown in the air, above the ground 254). The radar ormicrowave beam 256 from the module 248 extends in a cone 258 toadequately cover the ground 254 so as to provide the correct measure ofheight on a first return bases (that is, any portion of the beam 256which first creates a Doppler signal sets the height; other heightmeasurements can alternatively be used, including utilizing averagereturn data). A cone 256 of angle Φ (e.g., 25-70 degrees in solid angle)provides adequate coverage. The Doppler antenna signal fills the conicalbeam 256 so as to determine drop distance from any orientation of thevehicle (i.e., the snowboard 252), so long as that orientation relativeto ground is less than the angle Φ.

[0247] The Doppler module 248 may also be used as an airtime sensorsince its signal strength or form changes when the vehicle 252 is offthe ground. This change of signal is thus detected by the controllersubsystem to determine airtime.

[0248]FIG. 12 shows a representative top view for one other snowboardconstructed in accord with the invention. Specifically, a snowboard 270,with boot holder 271, incorporates a sensing unit 272 constructedaccording to the invention. The unit 272 has a display 274, a userinterface 276 that provides a user with buttons to selectively accessperformance data, as described above, and one or more sensors 278 toprovide data to the controller subsystem to quantify performance data.One sensor 278, for example, can include the Doppler module 248 of FIG.11.

[0249]FIG. 20 illustrates one embodiment of a bump skier 598 utilizingtwo power sensing units 600 in a mogul competition on a slope 612 (notethat the skier is grossly over-sized relative to the slope 612, forpurposes of illustration). One power sensing unit 600A mounts to the ski602 (or alternatively to the user's lower leg 604 a), and another powersensing unit 600B mounts or attaches to the user's upper body 604. An RFsignal generator 606 communicates (via antenna 606 a) the power valuesto a controller 607 (e.g., similar to the computer and server 74, 82 ofFIG. 1B) at a base facility 608 (e.g., where the judges for thecompetition reside). Those skilled in the art should appreciate that oneor both power sensing units 600 can communicate the information to thebase 608, as shown; however, one power unit can also communicate to theother power unit so that one unit 600 communicates to the base 608.However, in either case, an RF transmitter is needed at each sensingunit 600 (similar to the data transmit section 22, FIG. 1A).Alternatively, other inter-power meter communication paths are needed,e.g., wiring, laser or IR data paths, and other techniques known tothose in the art, such as discussed herein.

[0250] The combined signals from the units 600 provides a forcedifferential between the lower legs 604 a and the upper body 604, givingan actual assessment of a competitor's performance. A computer 607 atthe base station 608 divides one signal by the other to get a ratio ofthe power values measured by the two units 600 during the run. The units600 start transmitting data at the starting gate 610 and continue totransmit data to the base 608 during the whole run on the slope 612. Theunits 600 can also be coupled to the user via a microphone 614 (and wire616) to provide a hum or pitch which tells that user how effectivehis/her approach is. Although it is not shown, one or both units 600have controller subsystems so as to enable the features described hereinin connection with power sensing units. For example, a microprocessorcan be used to provide a power measurement in “g's” for the competitoronce she reaches the base 608.

[0251] Those skilled in the art should appreciate that one of the units600 can alternatively process the power values (e.g., divide theinstantaneous power value of one unit by the power value of the secondunit, to provide a ratio) generated by each of the units and cantransmit a ratio of the values to the base station 608, rather thanrequire the base station to perform the calculation.

[0252] One accelerometer-based vibration and shock measurement system(e.g., a power sensing unit) 620 of the invention is shown in FIG. 21.System 620 measures and processes accelerations associated with variousimpact sports and records the movement so that the user can determinehow much shock and vibration was endured for the duration of the event.The duration is determined with a simple start stop button 622, althoughduration can alternatively start with an automatic recording that isbased on the measured acceleration floor (or by an event such astriggered by the start gate 610, FIG. 20).

[0253] In system 620, vibrations and shock associated with skiing orexercise are measured by the use of an accelerometer 624 (or othermotion or force-measuring device, e.g., a microphone or piezoelectricdevice) as the power sensor and of conditioning electronics 626 withinthe controller subsystem. The accelerometer 624 typically is AC-coupledso that low frequency accelerations, or the acceleration due to gravity,are ignored. The accelerometer output is then conditioned by passing thesignal through a band pass filter within the electronics 626 to filterout the low frequency outputs, such as the varying alignment to thegravity vector, as well as the high frequency outputs due to electricalnoise at a frequency outside the performance of the accelerometer 624.The resulting signal is one that has no DC component and that is bipolarsuch as the waveform shown in FIG. 22.

[0254] The system 620 thus conditions the signal and remove the negativecomponents of the waveform in FIG. 22. This is done, for example, byrectifying the output of the bandpass signal. Since a positiveacceleration is likely to be accompanied by a negative of the same area,the area of the positive may be doubled to obtain the area of thepositive and negative. The signal may also be processed by an absolutevalue circuit. This can be done via an Operational Amplifier circuitsuch as the one shown in the National Semiconductor Linear ApplicationsData Book Application Note AN-31, which is herein incorporated byreference. In accord with certain processes, known to those skilled inthe art, positive values become positive; and negative values becomepositive. By way of example, the waveform of FIG. 22 is processed, forexample, to the waveform of FIG. 23.

[0255] A unipolar waveform like the one shown in FIG. 23 is thenintegrated over time by the system 620 so that total acceleration isaccumulated. This can also be averaged to determine average shock. Thesignal of FIG. 23 is therefore processed through an integrator (withinthe electronics 626 or the microprocessor 628) which will result in thesignal shown in FIG. 24. A power value can then be displayed to a uservia the display 630 (e.g., such as the display 24 c or 52, FIGS. 1A and1B).

[0256] The period of integration may be a day or simply a single rundown a slope; or it may be manually started and stopped at the beginningand end of a workout. The output is then fed into a logarithmicamplifier so that the dynamic range is compressed. The logarithmicamplifier can be provided within the microprocessor 628.

[0257] At any stage, the system 620 can be fed into an analog-to-digitalconverter (such as within the electronics 626) where signal processingis done digitally. The output of the accelerometer 624 should anywaypass through an anti-aliasing filter before being read by amicroprocessor 628. This filter is a low pass filter that ensures thehighest frequency component in the waveform is less than half thesampling rate as determined by the Nyquist criteria.

[0258] The accelerometer 624 output can also be processed through an RMScircuit. The Root Mean Square acceleration is then determined from thefollowing formula:$A_{R\quad {MS}} \approx {\frac{1}{T}\left\lbrack {\int_{0}^{T}{{A^{2}(t)}{\partial t}}} \right\rbrack}^{\frac{1}{2}}$

[0259] where T is the period of the measurement and A (t) is theinstantaneous accelerometer output at any time t. The period T may bevaried by the user (i.e., to control the power period) and the output isa staircase where each staircase is of width T. This is thenpeak-detected and the highest RMS acceleration is stored; and an averageacceleration and a histogram are stored showing a distribution of RMSaccelerations. These histograms are displayed on a Liquid Crystalgraphical display 630, for example, as a bargraph.

[0260] An alternate embodiment is to record the signal in time andtransform the signal to the frequency domain by performing a Fouriertransformation of the data (such as within the electronics 626 or themicroprocessor 628). The result is a distribution of the accelerationsas a function of frequency which is then integrated to determine thetotal signal energy contained (preferably over a frequency range). Thedistribution is, again, plotted on the LCD display 630.

[0261] Data may also be acquired by the accelerometer and telemetered tothe electronics 626 via an RF link 631 back to a remote base 632 forstorage and processing (e.g., such as at the base station 70, FIG. 1B).This enables ski centers to rent the accelerometer system 620 which isthen placed on a ski (or snowboard) to record a day of activity. Aprintout can also be provided to the renter at the end of the day.

[0262] A separate memory module or data storage device 634 can also beused to store a selected amount of time data which can be uploaded atthe end of the day. The data can be uploaded itself via a Infrared linkreadily available off the shelf, as well as through a wire interface orthrough an RF link 631.

[0263] The system 620 is particularly useful in impact sports thatinclude mountain biking, football, hockey, jogging and any aerobicactivity, including volley-ball and tennis. Low impact aerobics havebecome an important tool in the quest for physical fitness whilereducing damage to the joints, feet and skeletal frames of theexerciser. The system 620 can be integrated within a shoe and may thusbe used by a jogger to evaluate different running shoes. Alternatively,when calibrated, the system 620 is useful to joggers who can gate it toserve as a pedometer. The addition of a capacitor sensor in the heelhelps determine average weight. A sensor for skin resistivity mayadditionally be used to record pulse. The shoe can also record the stateof aerobic health for the jogger which is of significant interest to aperson involved in regular exercise. The system 620 can also be used toindicate the gracefulness of a dancer while they develop a particulardance routine. A football coach may place these systems 620 in thehelmets of the players to record vibration and shock and use it as anindicator of effort, or in the “football blocking dummies” to quantifyplayer effort.

[0264] In skiing, the system 620 has other uses since a skier glidesdown a mountain slope and encounters various obstructions to a smoothride. Obstructions such as moguls cause the skier to bump and to induceshock. This shock can be measured by the accelerometer 624 andaccumulated in a memory 634 to keep a record of how much shock wasencountered on a particular ski run. Exercisers may use such a system620 to grade their ability to avoid impact. A jogger may use the system620 to evaluate their gate and determine their running efficiency. Thisbecomes important with a greater emphasis being placed on low impactaerobics.

[0265] Those skilled in the art should appreciate that otherimprovements are possible and envisioned; and fall within the scope ofthe invention. For example, the system 620 mounted on a ski may be usedto determine the total shock and vibration encountered by a skiertraveling down a slope. Mounting an additional accelerometer 624 abovethe skier's hip allows an isolation measurement between upper torso andski, as described above. This can be used to determine how well atrained skier becomes in navigating moguls. This measurement of theisolation is made by taking an average of the absolute value of theaccelerations from both accelerometers 624. The ratio of the twoaccelerations is used as a figure of merit or the isolation index (i.e.,the ratio between two measurements such as on the ski and the torso,indicating how well the mogul skier is skiing and isolating kneemovement from torso movement).

[0266] To avoid the complications of gravity affecting the measurementsof system 620, a high pass filter should be placed on the accelerometeroutput or within the digital processor sampling of the output. Allanalog signals should have antialiasing filters on their outputs whosebandwidth is half the sampling frequency. Data from the accelerometers624 is preferably sampled continuously while the circuits are enabled.The processor 628 may determine that a ski run has started by a rise inthe acceleration noise floor above a preset trigger and at a setduration. In another embodiment, a table is generated within theprocessor of each sufficiently high acceleration recorded from the ski.The corresponding upper torso measurement may also be recorded alongwith the ratio of the two measurements. The user can additionallydisplay the n-bumpiest measurements taken from the skis and display theisolation index.

[0267]FIG. 25 shows a sport vehicle 700 (here shown as a snowboard)mounted with a GPS sensor 702 (and antenna 702 a) that is coupled to acontroller subsystem 704 such as described herein. The GPS sensor 702serves the functions of one or more of the sensors 14, FIG. 1A. As knownin the art, GPS receivers such as the sensor 702 provide absoluteposition in terms of altitude and earth location. By monitoring thesignal from the GPS sensor 702, speed, height and loft time are directlydetermined. For example, at each signal measurement, a difference iscalculated to determine movement of the vehicle 700; and that differenceis integrated to determine absolute height off of the ground, distancetraveled, speed (i.e., the distance traveled per sample period), andairtime. FIG. 25 thus illustrates a sensing unit which includes a GPSsensor 702 (operating as one or more of airtime, speed and drop distancesensors) and a controller subsystem 704, such as the subsystem 12 ofFIG. 1A.

[0268]FIG. 47 illustrates one GPS-based system of the invention,including a GPS receiver 1400 with an antenna 1401. The antenna is smallbecause GPS operates at an extremely high frequency. The antenna 1401may be mounted with a backback, of the user, containing the GPSreceiver. The receiver is powered by a battery back 1402 which alsopowers a microprocessor 1403. The microprocessor 1403 takes data fromthe GPS receiver 1400 and stores it as a position in random accessmemory RAM 1404. The data is preprocessed according to a program storedin Read Only Memeory ROM 1405. The processor ROM 1405 can also containstored maps with which to determine skier performance, allowing theprogram to become an expert system to, for example, identify trailfeatures or problems. The user interfaces with the microprocessor 1403via the peripheral interface 1406. Examples of a peripheral interfaceinclude keyboards, displays, etc. A panic button can be included withthe interface 1406 to inform a base station of trouble. The warning issent with exact location so that the rescue team (e.g., the ski patrol)can easily find the stricken person (e.g., skier).

[0269] An enhancement to the above system utilizes differential GPS.Differential GPS makes use of the property that a fixed receiver in aknown position can be used in conjunction with a non-stationary GPSreceiver with the effect that many of the large errors are rejected. Theresult is a more accurate position solution for the moving receiver. Inthe preferred embodiment, a user carries the reciever 1400 and the basestation houses the differential model, as known in the art.

[0270] For skiing and other similar sports, the user is given a GPSreceiver and an RF link (e.g., a transmit section 22, FIG. 1A) so that acentral computer at the base station lodge (e.g., station 70, FIG. 1B)knows the location of every user. Such locations may then be broadcastto the skier for display in a set of goggles using a heads-up display.

[0271]FIG. 26 shows a strain gauge 720 connected to a controllersubsystem 722, such as the subsystem 12 of FIG. 1A. In the illustratedembodiment, the sport vehicle is a ski or snowboard 724. Those skilledin the art understand that strain gauges can detect stress associatedwith the surface that the gauge is mounted upon. The gauge 720 thussenses when there is little or no stress on the snowboard 724, such aswhen the snowboard 724 is in the “air”; and the subsystem 722 thendetermines airtime from that relatively quiescent period. FIG. 26 thusillustrates a sensing unit which includes a strain gauge 720 as anairtime sensor and a controller subsystem 722. The sensing unit 720/722can further provide factors such as power, by utilizing the signalgenerated by the strain gauge 720 as a measure of the punishment thatthe user applies to the vehicle 724. Accordingly, the gauge 720 canoperate as a power sensor in addition to an airtime sensor.

[0272] In an alternative embodiment, the element 720 is a temperaturegauge that senses the change in temperature when the ski 724 leaves theground. This change of temperature is monitored for duration until itagain returns to “in contact” temperature. This duration is then equatedto “airtime” or some calibrated equivalent (due to thermal impedance).Note that the impedance of air is different from snow; and hence thatchange can also be measured to determine airtime.

[0273] In an alternative embodiment, the element 720 is a load cell,known in the art, such as a strain gauge bridge, or other force-sensingmeans, such as force sensing resistors (FSRs). A unit incorporating suchelements operates as described above.

[0274]FIG. 27 shows one speed, airtime and power sensing unit 740,constructed according to the teachings herein, and mounted to a sportingvehicle such as the ski 741. The unit 740 has an RF transmitter 742(e.g., similar to section 22, FIG. 1A) to communicate signals from theunit 740 to a watch 744 worn by the user (not shown). In this manner,the user can look at the watch 744 (nearly during some sportingactivities) to monitor performance data in near-real time. A small watchdisplay 744 a and internal memory 744 b provide both display and storagefor future review.

[0275] The devices for measuring speed, airtime, drop distance and poweras described herein can oftentimes be placed within another componentsuch as a user's watch or a ski pole. For example, the power system 620of FIG. 21 is readily placed within a watch such as watch 744, andwithout the unit 740, since power integration can be done from almostanywhere connected to the moving user. Likewise, airtime measurementthrough the absence of a spectrum, such as shown in FIG. 6, can also bedone in a watch or a ski pole. Speed measurements, however, are muchmore difficult if not impossible to do at these locations because of thelack of certainty of the direction of movement. However, with theincreased performance and size reductions of guidance systems withaccelerometers (see FIGS. 9 and 10), even this can be done.

[0276]FIG. 28 illustrates one drop distance sensing unit 800 fordetermining drop distance from a skier or snowboarder 801 (or othersport enthusiast, e.g., a mountain biker, skateboarder, roller-blader,etc.). The unit 800 includes an antenna 802 and a GPS receiver 804. TheGPS receiver operates such as known in the art. Although the unit 800 isshown on the skier's waist 806, the unit 800 can also be coupled to thesnowboard 808 or it can be constructed integrally with the user's watch810. In the embodiment shown, the unit 800 can include a second antenna812 (or other data transfer mechanism, including IR techniques) whichcommunicates with the watch 810 so as to send performance data thereto.

[0277]FIG. 29 illustrates a block diagram of the drop distance sensingunit 800, including further detail therein. A microprocessor 809connects with the GPS receiver 804 to process GPS data. In particular,the GPS data is known to include three dimensional data including heightoff the earth's surface. The processor 809 thus processes the data atpredetermined intervals, e.g., about 1 second or less, to determine thechange of height from the last measurement. Accordingly, when airtime isdetermined, according to the teachings herein, the device 800 alsodetermines drop distance for that interval. The drop distanceinformation is stored in internal memory 812 so that it can be retrievedby the user or transmitted to a data unit such as the watch 810. Recordsof drop distance can also be stored within the memory 812 such that apeak drop distance and a series of drop distances can be stored andretrieved by the user at a later time. The device 800 also includes abattery 814 and other interconnections and processing electronics (notshown) to operate the device 800 and to provide drop distance data, asdescribed in connection with FIGS. 1A and 1B. A data transmit section816 (e.g., the section 22, FIG. 1A) transmits data via an antenna 816 a(or other technique), as desired, to the watch 810 or to other displaysor data units, or to the base station, such as discussed herein.

[0278] Evaluation System

[0279] The sensing units described herein can be complex, and requirelengthy evaluation to provide a robust system. To evaluate such units, adata evaluation system was developed, as described next. The dataevaluation system provides a flexible data recording unit that hasapplicability in several circumstances where large amounts of data arecollected in adverse and remote environments.

[0280] As shown in FIG. 30, the Data Acquisition system 899 includesfive main components on a data acquisition/playboack board:

[0281] Data Recorder/Player 900

[0282] PC Interface 902

[0283] Analogue Motherboard 904

[0284] Analogue Input Interface Boards 906

[0285] Analogue Output Interface Boards 908

[0286] To record information, the Data Recorder/Player board andAnalogue Mother Board 900, populated with the required Analogue InputInterface Boards, are placed in a box, connected by a small back plane.Once the data has been recorded, the Data Recorder/Playback Board 900 isremoved from the box, and connected to the PC Interface board. The PCthen controls the downloading of data to file.

[0287] The overall size of the Recording Package is 2½″ wide, 5½″ deep,and 4½″ tall. All sensors are external, and may or may not be housed inboxes.

[0288] The data recorder and player 900, FIG. 31, is the heart of thesystem 899. It includes a block of memory 910 for holding the sampleddata values, controlling logic 912, and interfaces 914 a, 914 b.

[0289] The Data Recorder/Player Board (DRPB) 900 always handles 32 bitsof data. It is configured to either Record or Playback the data at arate of one word (32 bits) every 15.6 □S (approx. 64 KHz). The controlinterface 914 provides signal to interface to the PC Interface board andAnalogue Mother Board.

[0290] The Control Logic 912 also provides refresh cycles for thedynamic RAMs. The Memory 910 consists of any 72-pin SIMM modules. Thesemust be matched in the same manner as when used in a PC. (i.e. one 8 Mbcannot be mixed with one 16 Mb module.) This provides a limit of 512 Mbof RAM, which will give a maximum of 134217728 samples. This isequivalent to 34 minutes and 53 seconds. However, the larger SIMM's arephysically taller than standard-sized devices and are very expensive. Inpractical terms, two 64 Mb SIMMs (128 Mb) provide 8 minutes and 43seconds of data recording at 64 KHz.

[0291] The recorder can be paused during testing. Longer recordingperiods make annotation of the data (and data handling) more difficult.If this limit is acceptable, two of the SIMMs can be removed from theirsockets in the DRPB 900, to reduce its size.

[0292] The DRPB 900 has its own NiCAD battery (attached to the board forsafety) such that the board can be removed from the box on the ski andtaken to the PC for downloading.

[0293] PC Interface

[0294] The PC Interface 902 allows the DRPB 900 to be connected to theparallel port of a PC. It requires a bi-directional port (EPP). Thedesign uses two MACH 210 s, and allows the PC to control the upload anddownload process completely. The current download/upload rate achievedis 8 Mbytes/minute which is generally acceptable.

[0295] Analogue Mother Board

[0296] The Analogue Mother Board (AMB) 904 controls the sampling of thedata on the Analogue Input Interface boards (AIIBs) 906. It presents theData Recorder/Player 900 with 32 bits of data for each recording period.Data from the AIIBs 906 are multiplexed. The programming of the AMB 904determines the sampling rates and position of the data in the 32-bitword for the AIIBs 906. If a different combination of AIIBs is required,the AMB 904 is reprogrammed. Therefore, the control logic on the AMB 904is held in an AMD MACH 211 which is a flash device, programmable whilststill on the board using a JTAG connector (thus a notebook PC with aparallel port can reconfigure the board.)

[0297] As shown in FIG. 32, the Control Logic 912 inserts the real timeclock 916 value into one channel (probably an 8 KHz channel). This willsimply be a counter counting at a minimum frequency of 8 KHz, whichallows the analyzing software to detect when the recording was paused.

[0298] Analogue Input Interface Boards

[0299] The Analogue Input Interface boards 906 are small daughter boardswhich plug in vertically to the Analogue Mother Board 904 (i.e., intothe slots 918, FIG. 32). The Mother board 904 will allow 8 of theseboards to be connected at once. This design allows an interface board tosuit the signal to be recorded. This is then combined with otherinterface boards to allow recording of a combination of signals, asrequired.

[0300] As shown in FIG. 33, the A/D converter 920 is a serial device;thus reducing the number of pins required and the level of boardcomplexity. The board space available for Analogue Signal Conditioning922 is limited. The Pressure Sensor AIIB 906 (i.e., that boardincorporating a drop distance sensor, discussed above), shownschematically in FIGS. 34A and 34B, provides an example of the sizelimitations, and the complexity level limitations on the circuitry.Specifically, the circuit 930 of FIGS. 34A and 34B is an example of anAIIB 906 for a SenSym Pressure sensor. It uses four op-amps and variouscapacitors and resistors to provide the required signal conditioning.

[0301]FIG. 35 exemplifies a layout board 940 for circuit 930, FIGS. 34Aand 34B, used to connect to the AMB 904. The height of the board 940 is0.9″, and the width is approximately 2½ inches.

[0302] Preferably, one AIIB 906 incorporates a Voice Annotation Channel,so that data can be annotated by voice concurrently with dataacquisition. The AIIB 906 for the Voice annotation channel can have asimple tone generator connected to an external button that is operatedby the skier. This will inject a tone when pressed onto the voicechannel to allow marking in the annotation of special places.

[0303] The analog interface boards 908 are similar to the AIIBs, buthave a DAC rather than ADC components. They allow the system to generatesignals as recorded from the sensors. Thus a new board design can betested on a virtual slope on the bench.

[0304] The data acquisition system thus permits the capture of data,real time, to evaluate sensors such as altimeters used in a dropdistance sensor, described herein. Two exemplary altimeters, forexample, are the SenSym SCX15AN Pressure sensor and the SenSym SCX30ANPressure sensor.

[0305] As discussed herein, many embodiments of the invention utilizepiezo foils, such as within airtime, power, and speed sensors. Thesefoils for example include those foils from AMP Sensors, such as the AMPDT0-028K foil or the AMP LDT1-028K foil. Similarly, an accelerometerlike the AMP ACH-01-03 accelerometer can be used to generate vibrationdata (this sensor was in fact used to collect the data of FIG. 6).

[0306] Another pressure-based drop distance sensing unit 1000 of theinvention is shown in the block diagram of FIG. 36. The unit 1000includes a pressure sensor 1002, as described above, and is used todetermine altitude. GPS, as described above, may also be used inconnection with the unit 1000. The pressure sensor altimeter 1002 isused to determine ambient pressure. As altitude changes, so does thepressure. The pressure sensor 1002 indicates pressure by an analogvoltage. That voltage is conditioned by the conditioning electronics1004 so that the output data is filtered, well-behaved and has anappropriate scale factor. The electronics 1004 also typically filter thesignal to prevent aliasing when sampled by the controller subsystem1006. After conditioning, the data is converted to a digital word by A/Delectronics 1008 for the microprocessor 1006. The data is thusrepresented as an eight, twelve or sixteen bit word. It is then read bythe microprocessor 1006 and is interpreted as altitude.

[0307] As illustrated in FIG. 37, the processor 1006 includes residentsoftware that schedules the reading of data and its manipulationthereof. The core shell of software is the Real Time Operating System1010. This may be purchased off the shelf by companies such as ReadySystems. These programs process tasks according to user selectedpriorities so that every task is executed within a software controlframe. The part of the software that reads the pressure sensor output(from the A/D 1008′) is called the Input Output Driver or I/O Driver1012. This program may be executed on a regular basis automatically ormay be the result of an interrupt. In the event of an Interrupt, theprocessor 1006 automatically launches an interrupt service routine orISR. The purpose of an ISR and I/O Driver 1012 is to get the data intothe processor's memory so that an application program may use theinformation. Filtered by the I/O Data 1013, the application 1014 is thesoftware that interprets the data, such as to determine altitude 1016.The data may then be stored in memory for other applications 1014 tooperate on the data, use it for decision making, or pass it on to otherI/O Drivers for output.

[0308] The processing of altimeter data from the pressure sensor 1002 isa matter of eliminating the low and high frequency noise from themeasurement. In this embodiment, this is done by cascading a high passwith a low pass filter. The Low pass filter is selected by determiningthe sampling rate and ensuring that the highest frequency component inthe signal passed through the filter is half the sampling rate, known asthe Nyquist criteria. Frequencies that are higher than half the samplingrate will result in aliasing. This means that the spectrum will bedistorted and the original signal is not accurately reconstructed.

[0309] The high frequency component of the cascaded high pass, low passfilter is thus selected by the maximum rate of descent the skier willtravel. The higher the low pass filter, the faster the altimeter tracksthe skier. Since the skier is limited by inertia and kinematics (thebasic laws of motion) the rate of altimeter change is not high by signalprocessing standards. If a skier travels at 100 ft per second, this isabout 68 miles per hour, which means that if they move along truevertical their altitude would be changing at 100 ft/sec. If the changein output voltage goes from DC to 100 Hz, then the low pass filter alsoneeds to pass the 100 Hz.

[0310] The low frequency of the high pass, low pass filter is related tohow slow the signal changes. In this case it is limited by the frequencyresponse of the altimeter and the slow changes associated withatmospheric fluxuations.

[0311]FIG. 38 shows a “shock” or “G” or power digital watch 1020constructed according to the invention. As in normal watches, a band1022 secures the watch 1020 on a user's wrist so that the watch face1024 can be viewed. A crystal 1026 provides the primary window throughwhich to view data such as time on the display 1028. A user can adjustthe time through a knob such as knob 1030.

[0312] The watch 1020 also holds a power sensing unit 1032, as describedherein. The unit 1032 utilizes either its own microprocessor (e.g., acontroller subsystem), or augments the existing microprocessor withinthe watch 1020 to provide like capability. The unit 1032 is controlledby interface buttons 1034 a, 1034 b, such as to provide ON/OFFcapability and to display power performance data instead of time on thedisplay 1028.

[0313] The watch 1020 of FIG. 38 thus provides “power” without theadditional mounting of a sensing unit on a vehicle. Rather, thisembodiment takes advantage of the fact that many sports include wavingand movement of the user's arm (e.g., tennis and volley-ball); and thuspower is determined through the techniques herein to inform the user ofthis performance data, through the watch 1020.

[0314]FIG. 39 illustrates another watch system 1040 for measuring powerand informing a user of that power. As above, the watch 1042 is made tomount over the user's wrist. The watch 1040 functions as a normal watch,including, for example, a display 1044 to tell the user time (e.g.,“10:42 PM”). Another portion of the watch includes a power sensing unit1045, a processor 1048, force sensing element 1050 (e.g., a power sensorsuch as an accelerometer, or alternatively a microphone) and circuitry(not shown) to drive a display that informs the user of power. Theprocessor 1048 processes the force data from the sensor 1050 and sends asignal to the display 1052 so that the user can see the powerperformance data (e.g., “50 G's”). The units on the display 1052 neednot be actual units, such as G's, but relative units are acceptable tocalibrate to other users and to repeated activity by the same user. Acontrol knob 1054 provides access to the unit 1045 in a manner similarto the user interface buttons of FIGS. 1A and 1B.

[0315] Those skilled in the art should appreciate that an altimeter canalso be placed in the watch 1040 so that, as above, the user is informedof drop distance. The button 1054 can also enable control of the unit1045 so that one of drop distance, or power, is displayed on the display1052. This dual drop distance and power watch embodiment is described inmore detail in FIG. 40.

[0316]FIG. 40 illustrates one block diagram of a power/pressure watchsystem 1060, constructed according to the invention. An altitude orpressure sensor 1062 as discussed above is conditioned by conditioningelectronics 1064 which filter and scale the sensor's output. The data isthen converted to digital by the Analog to Digital electronics 1076. Thedata is then read by the microprocessor 1066, wherein the data isprocessed by software and interpreted as altitude. The watch system 1060includes a keyboard interface 1068 to set the time and the differentperformance data modes, as commanded by the user. Time is displayed onthe watch display 1070, as normal.

[0317] System 1060 can further include an accelerometer 1072 whichsenses vibration and shock, as described herein, and which provides avoltage that is proportional to acceleration. This output is thenconditioned by the conditioning electronics 1074 for scaling andfiltering (such as through a combination of low pass and high passfiltering): the high frequencies limit is selected by anti-aliasingrequirements while the low frequency limit is determined by lowfrequency noise rejection. The data is then sampled by the analog todigital electronics 1078 and read into the microprocessor 1066.

[0318] Drop distances may thus be determined by various sensors,including accelerometers, differential Global Positioning System (GPS)receivers, and pressure sensors, as discussed above. These sensors maybe used in conjunction with airtime logic—which for example senses theabrupt change in the vibratory noise floor, potentially indicating theskier leaving contact with the ground—to give useful drop distancescorresponding to airtime.

[0319] Accelerometers can also be used to determine airtime and theonset of free-fall. By using accelerometers to look at the skivibration, airtime can be determined by absence of the vibratingspectrum, suggesting that the skis are no longer rubbing along theground. Generally, this corresponds to the high frequency component tothe acceleration signal. Accelerometers in the prior art also measurethe acceleration due to gravity, which tends to change slowly. When abody free-falls, the force on the seismic mass associated with theaccelerometer is zero because the seismic mass is no longer restrained.An accelerometer suite that measures acceleration in three translationaldirections will sum to zero in a free-fall. When the gravityacceleration returns, noted by the return of the low frequencyacceleration floor, as well as by the return of the high frequency noisefloor from skis rubbing on the ground, the system can determine theduration of free-fall—i.e., drop distance. The minimum distance dtraveled in this free-fall along the axis of gravity known as truevertical may be determined by the formula d=v_(o)t+½ gt², where d isdistance traveled downward, g is acceleration due to gravity 32ft/sec^(2.,), v_(o) is the initial velocity downward, and t is thenumber of seconds of free-fall. If the initial velocity v_(o) is notknown then the minimum distance d_(min) can be determined by the rest ofthe equation d_(min)=½gt².

[0320]FIG. 9 showed the hardware block diagram for an accelerometersuite 207 capable of determining loft and free fall. The diagramincluded three linear accelerometers whose output are conditioned byelectronics that strengthen and filter the signals. The output of theconditioning electronics is then fed into interface electronics thatconvert the signals from analog to digital.

[0321]FIG. 41 illustrates a top view of one preferred system 1100 fordetermining power and/or airtime (and/or speed discussed in more detailbelow). The system 1100 includes a sensing unit 1100 a with housing 1102mounted to a snowboard 1104 (alternatively, the system 1100 can bemounted to a ski, windsurfing board, bike, etc.) and a data unit 1100 b,such as a data collection watch 1112 (such as the datawatch by Timex®).The housing 1102 forms an enclosure for the sensor, here illustrated asa piezo strip 1108 such as made by AMP Sensors, in Pennsylvania. Thestrip 1108 connects with the housing 1102 to measure sound within thebox 1102. The box 1102 thus serves to amplify the sound heard throughthe ski 1104, and also compresses air within the box 1102 in a mannerthat is indicative of the force experienced by the box and thus the ski1104. Accordingly, the strip 1108 measures not only sound, but aforce-related factor that is used to determine power. In this manner, amicrophone (e.g, the strip 1108) is suitable to measure both airtime andpower. Further, by monitoring the pitch or signal strength of the soundwithin the box, a speed can be correlated with the sound. Accordingly,by a single microphone such as a piezo strip 1108, airtime, power andspeed (or at least motion) are provided. A controller subsystem 1110connects to the strip 1108 to process transducer data; and thatprocessed data is transferred, for example, to the watch 1112 worn bythe user by way of infrared energy signals from a diode/detector pair1114 a/b or other similar optical data transfer devices. The units 1100a and 1100 b preferably permit communication between units, eitherdirection.

[0322] Other transducers, e.g., an accelerometer or altimeter 1116 canalso be placed in the box 1102 for processing and transfer to the user'swatch 1112. The box 1102 is preferably sealed against environmentaleffects so as to protect the electronics therein. It is thus similar tothe housing 32 of FIG. 1A. Because of the watch 1112, there is noseparate need for a display in the sensing unit 1100 a. A battery (notshown) powers the unit 1100 a.

[0323] Another microphone such as the strip 1108 a can also be includedwithin the unit 1100 a to provide additional speed sensing capability,as described below.

[0324]FIG. 42 illustrates that at the onset of airtime, the controllersubsystem can trigger a drop distance calculation. Specifically, at anairtime sensed by an airtime sensing unit, a drop distance sensor—e.g.,a GPS receiver, altimiter, or accelerometer—is polled to determine thechange in vertical direction. In the event of a vertical drop, the firstderivative in the z direction (True Vertical) should be a maximum. Thesignal flow diagram of FIG. 42 illustrates this logic:

[0325] Specifically, loft condition is first determined by the airtimesensor of block 1200. This data state is determined, for example, by thesudden absence of noise in the ski, causing an abrupt change in the nearnoise floor. The next data state is characterized by blocks 1202, 1204and 1203. In state 1202 an altimeter is polled to determine if altitudeis changing at a high rate, such as a rate associated with free fall. Ifso, the drop distance data is accumulated for the duration of the highfree fall rate and the airtime. The state 1204 is similar to that of1202, except for GPS receiver signals. In state 1204, GPS data isevaluated for a high rate of change in the Z direction. If there is ahigh free fall rate, the data is accumulated for as long as both thehigh rate and loft time are valid. The state 1203 corresponds to a datastate using accelerometer data evaluation for airtime. As before, if theuser is in free fall, the accelerometer does not experience anacceleration due to gravity. During this condition, drop distance datais accumulated during the airtime to determine vertical drop. The end ofairtime signifies the end of the vertical drop, and state 1206 isreturned. The distance of the drop is provided by the accumulation ofthe altimeter change, the change in GPS vertical height, or the durationof the accelerometer free fall and the laws of physics, as describedherein.

[0326]FIGS. 43 and 44 provide vibrational data corresponding toaccelerometer data at less than 2 mph, FIG. 43, and greater than 15-20mph, FIG. 44. The data acquisition system was the same as for the dataof FIG. 6. As a ski moves faster over the surface of the snow, more ofthe energy from the spectrum is associated with the higher frequencycomponents. Specifically, it is readily seen that the FIG. 44 has morepower at higher frequency components. By segmenting and “binning” thesefrequencies, energy is isolated to such frequencies so that it can becompared to calibrated speed data at those frequencies. This isdescribed below.

[0327] Note first that a microphone can provide basically the sameinformation as the accelerometer above (that is, the data of FIGS. 43and 44 appear similar to microphone data taken within a unit such asdescribed in connection with FIG. 41), at least in frequency andrelative magnitudes. Microphones are cheaper than accelerometers, andthus they are preferred for production reasons.

[0328] With regard to FIG. 45, a force measuring sensor such as amicrophone or accelerometer generates a voltage signal indicative of thespectra such as within FIGS. 43 and 44. This voltage 1300 is passedthrough an array of temporal filters which “bin” the appropriateresults, according to frequency, such as shown in block 1302. Thetemporal binning of block 1302 can include a series of analog networksthat pass specific frequencies only. For each frequency bin, the data isprocessed by modules 1304: the data is first rectified at block 1306 anda capacitor 1308 charges over the time constant of an A/D 1310 tointegrate the signal of those frequencies; whereinafter the switch 1312discharges in time for the next sample. The output is then summedaccording to frequency, for subsequent summing.

[0329] Those skilled in the art should appreciate that the process ofFIG. 45 can be done within a DSP, wherein the steps of blocks 1302 and1304 are accomplished through software modules. Accordingly, the unit 10of FIG. 1A can thus simply process the data 1300 within themicroprocessor 12 a, or the logic functionality can be maintained inanalog such as within the logic 12 c or within other electronics notshown.

[0330] In any event, the various frequencies are then binned. Forexample, the low frequency 0-1 Hz is binned into the first bin, the 1-10Hz frequencies are in the next, and so on (similar to the equalizerlight on the home stereo system). For each time T (set by the A/D orother time—which is preferably at a reasonably fast rate, e.g., 100 Hz),the power in each frequency is integrated and assigned an integer value,such as: a typical value within 0-1 Hz is 1, a typical value within 1-10Hz is 1, and so on. These values are integrated at a user selectedinterval (i.e., the power period). Further, the power values arepreferably standardized to every user, so if you have 5 seconds of peakpower activity, that will be saved—this number should be changeable to10 seconds or even 1-5 minutes. A table created by this technique mightappear as in Table I: TABLE 1 Typical Frequency Binning, for Speed,Airtime and/or Power 100—100 Frequency 0-1 Hz 1-10 Hz 10-100 Hz Hz A/DSample 1 1 .5 1 .1 A/D Sample 2 2  1 2 .3 A/D Sample 3 1  2 1 .4 A/DSample 4 2  1 3 .3 . . . . . . . . . . . . . . . A/D Sample n X1 X2 X3X4 SUM over 6 + . . . + 4.5 + . . . + 7 + . . . + 1.1 + . . . + time 1 −n X1 X2 X3 X4

[0331] With time 1−n corresponding to the power period, power values arefunctionally dependent upon the SUM values, either within some or all ofthe bins. Note that the bins of FIG. 45 and Table 1 are chosen forillustrative purposes only; and that other bin sizes and ranges can beused in accord with the invention.

[0332] Fortunately speed can also be determined through these SUMs(although the summing “period” should be much faster than for power, andshould typically be less than one second or even one tenth of a second).As noted above, there is a lot more high frequency content at fasterspeeds, FIG. 44, as compared to lower frequency content, FIG. 43. So,speed can also be correlated to such binned data, after obtaining asufficient database of samples (preferably corresponding to theparticular vehicle). Further, not all binning sections need to be usedin that correlation. For example, one of the binning sections mightreadily produce a four factor increase of power for 15 mph as comparedto 3 mph; and such increase is repeatable to correlated data.

[0333] Again, data for speed should not be integrated over time 1−n; butrather should be assessed for each sample or groupings of sample (e.g.,an average of samples over a {fraction (1/10)} ths period). If forexample a group of samples over any one second specify 15 mph data, thenthe speed sensing unit should report “15 mph event recorded”. If onlyone sample has this value, then it should be discarded since—relative to{fraction (1/10)}s intervals—the speed is substantially “steady state”.That is, an average of ten speed summations over one second should, onaverage, all report the same 15 mph event.

[0334] The data of Table 1 can be also used for power. In one preferredaspect, power is a factor which is scaled to the third derivative ofvertical distance moved with respect to time, essentially the change ofacceleration (in the perpendicular axis to the ski or snowboard, ifdesired, or some other orientation) as a function of time. Specifically,power can be measured as:${Power}\quad\therefore{\frac{\partial^{3}x}{\partial t} \approx \frac{\partial A}{\partial t}}$

[0335] where x is distance moved in the selected direction (here,vertical to the ski face), and A is acceleration in the same axis.

[0336] In summary, selectable integral periods for power (e.g., 5seconds, or 5 minutes, or other user-selected power period), and forspeed (e.g., less than one second) are preferable, in accord with theinvention. Note also that the filter bank 1302 is preferably adjustableand not limited to 0-1 Hz, 1-10 Hz, 10-50 Hz, and 50-250 Hz.

[0337]FIG. 46 shows illustrates the capture of data 1300′, such asdigital or analog data from an accelerometer, by a DSP 1304′ within asensing unit of the invention. The DSP converts data 1300′ to power byone of several disclosed algorithms: by evaluating one or more frequencyranges of the data 1300′, by determining vertical motion relative to aface of the vehicle and assessing that motion with an exponential factorfor a selected time period, or by determining a vertical velocityrelative to a face of the vehicle and assessing that velocity with anexponential factor.

[0338] Note also that airtime can also be isolated from the data ofTable 1. For airtime, the low frequency bins of 0-1 Hz and especially1-10 Hz will be very small; and the controller subsystem willimmediately identify this loss of power, in these binned frequencies.Since airtime can be less than one second, the moving averages whichintegrate the data should be substantially less than the airtimeminimum. Essentially, the airtime binning is a one-dimensionalconvolution between a rect function (defining the period) and the dataof the lower frequency bins. A similar convolution can be applied todetermine factors such as power and speed, except that the rect size islarger and different bins are likely used.

[0339] Power can be determined in other ways too, in accord with theinvention. Specifically, power can be defined as the rate at whichenergy E is expended. Power and work are related by:

P=dE/dt

[0340] By having an estimate of the energy associated with the user'smovement, over time, then an estimate is also available for the powerexpended by the user. The kinetic energy of a simple mass is expressedby:

E=½ mV²

[0341] Thus energy is proportional to velocity squared. Velocity, orspeed, is determined in several ways herein. For example, velocity canbe determined from an accelerometer by integrating acceleration overtime after subtracting the 1 g acceleration of gravity. In a sampledsystem, velocity at any point in time (at interval Δt) is equal to:

V≈ΣAΔt

[0342] where A is the measured acceleration with the 1 g accelerationremoved. Velocity is squared to obtain a quantity proportional to thekinetic energy:

E=V²

[0343] The total power over some finite time interval N is thusproportional to:$P \approx {\frac{1}{\left( {N - 1} \right)\Delta \quad t}{\sum\limits_{i = 1}^{N}\quad \left( {V_{i}^{2} - V_{i - 1}^{2}} \right)}}$

[0344] If for example the accelerometer is attached to a ski orsnowboard, then a significant portion of the measured acceleration maybe due to the oscillations of the ski/board at its resonant frequencies.These oscillation are the ski/board's response to its dynamic loadingenvironment and may not be indicative of the power that theskier/boarder experiences. It is therefore worthwhile to process theaccelerometer signal so as to reduce the contribution made by ski/boardvibration to the power measurement. The resonant frequencies of theboard and skis are significantly higher than the dynamics that theskier's body experiences. Thus, the contribution of the ski/boardresonant response to the accelerometer measurement can be reduced byapplying a low pass temporal filter to the data prior to integration.

[0345] One way of developing an algorithm to deal with extracting speedfrom acceleration data (or microphone data or other force sensingoutput) is through a neural network. A neural algorithm is one that isdeveloped through a learning process, including force sensing data fromthe sensor and speed data correlated during test. The neural algorithmbuilds a network that will process the data. It starts off by using asmall number of samples and a small number of stages. The output isderived by weighting factors on the samples and added together. Theoutput becomes a weighted average of the inputs, i.e., a multiple stagemoving average filter. The output is then compared with the speedwaveform and tested to see how well it produces the correct result. Ifthe test fails, the number of samples is then increased or the number ofstages is increased, or both. FIG. 48 illustrates an exemplary neuralnetwork 1498 windowing down acceleration data 1500 to achieve thecorrelated speed 1502. Specifically, FIG. 48 shows the construction of anetwork 1498 where four samples 1,2,3,4 are fed into four stages 1504,and where each sample is multiplied by a weighting factor or gain. Thenetwork 1498 is then tested to see if input data produces speed data. Ifnot the number of samples used as input are increased as are the numberof stages. At each network the relative gains are also changed to see ifthat will produce the required result.

[0346] Other Techniques for Speed Estimation

[0347] In accord with the invention, speed can also be determined basedupon the characteristics of the resulting friction-induced noisespectra. When the vehicle—be it a ski, snowboard, waterski, etc.—passesover the surface, the spectra will have a bandwidth content thatincreases with vehicle speed in a deterministic fashion (if one canassumes that the spatial spectral content of the surface is invariantwith respect to time and location). As such, the following describes atwo-sensor technique for estimating delay times of transport processes.The unit 1102 of FIG. 41 includes two such sensors—i.e., the two piezostrips 1108—which are suitable for such process measurements.

[0348] Consider the system 1600 depicted in FIG. 49. A ski or snowboard1602 is instrumented with two vibration sensors 1604 such as describedabove. These sensors 1604 are attached a distance “D” apart. The skimoves at a velocity “V” over the snow surface 1606. The front-mostsensor 1604 a provides a vibrational output s₂(t), a typical example ofwhich is plotted in FIG. 50. The rear-most sensor 1604 b provides avibrational output s₁(t), plotted in FIG. 51. Assuming that thecharacteristics of the snow surface 1606 which induce the response s₂(t)do not change significantly as the ski 1602 passes through a distance D,and that the speed of the ski 1602 does not vary significantly over thattime, then s₁(t) will essentially be a replica of s₂(t), delayed by anamount of time T. This is seen by considering the feature of thevibration spectra at time to in FIG. 50. This trace can be conceived ofas “sliding” along the time axis t to produce FIG. 51, except now theaforementioned feature of the time trace appears at time t₀+τ.

[0349] If one estimates the time delay t accurately, then one simplyuses the relationship DISTANCE=VELOCITY×TIME to infer the velocity V:$\begin{matrix}{V = {\frac{D}{\tau}.}} & (1)\end{matrix}$

[0350] This same methodology has been applied in measuring thecharacteristic propagation times (and thence speeds) of spatial featuresin turbulent flow over wings and other surfaces.

[0351] Since the vibrational input can be thought of in a local frame(the “sensor frame”) as a random process, one can use conventionalstatistical means to infer the delay time t, and thence V. Typically,this is done using correlation functions. Define the cross correlationfunction R₁₂(τ) as $\begin{matrix}{{R_{12}(\tau)} = {\lim\limits_{T\rightarrow\infty}{\frac{1}{T}{\int_{0}^{T}{{s_{1}(t)}{s_{2}\left( {t + \tau} \right)}\quad {t}}}}}} & (2)\end{matrix}$

[0352] A typical cross correlation function is plotted in FIG. 52 (notethat this cross correlation function depicts a system with twocharacteristic time delays, t₁ and t₂).

[0353] The most straightforward interpretations of cross correlationfunctions are in the context of propagation problems. For non-dispersivesignal propagation of the type considered here, even in the presence ofadditive noise associated with the sensors, one can show that$\begin{matrix}{{{R_{12}(\tau)} = {R_{22}\left( {\tau - \frac{D}{V}} \right)}},} & (3)\end{matrix}$

[0354] where R₂₂ is the autocorrelation of s₂(t). A typicalautocorrelation function is plotted in FIG. 53. Thus, the crosscorrelation of equation (2) will look like the autocorrelation of s₂(t)shifted by the amount D/V along the correlation time axis. Using thisfact, one can readily infer the delay time τ by searching for the peakmagnitude of the cross correlation function (whose construction isdescribed below), and then computing the velocity V using equation (1)since D is known. Thus, a two-sensor system will permit the measurementof the speed V independent of the spatial spectral content of the snowsurface.

[0355] Note that the separation D is shown with large separation forpurposes of illustration; when in fact that distance will typicallyreflect a small separation such as illustrated by the separation of thesensors 1108 of FIG. 41.

[0356] There are a few practical considerations to be kept in mind whencomputing R₁₂, and in interpreting its characteristics. First, unlikeautocorrelations, extraneous noise at the sensors 1604 a, 1604 b onlyreduces the relative contributions of individual correlation peaks andincreases the random error in the measurement; but it does not distortor bias the result, hence the time delay measured will be the true timedelay. Secondly, one should determine a priori if there are anysecondary propagation paths for the vibrational signal that first enterssensor 1604 a to reach sensor 1604 b before the ski slides over the snowthe distance D.

[0357] This may occur in skis or snowboards, as is shown in FIG. 54. Theboard/ski can support bending modes via flexing, which have acharacteristic (slowest) propagation speed “C_(B)”. Also, the materialwithin the board can support the equivalent of acoustic (sound) waveswithin it, with characteristic propagation speed “C_(P)”. This wouldlead to a cross correlation having two correlation peaks, each of whichcorresponds to the delay time associated with transmitting thevibrational input at 1604 a to sensor 1604 b via bending andcompressional waves, respectively. If these wave speeds are comparablewith the skier's speed V, then one will not distinguish skiing speedfrom the natural vibrational response of the board/ski 1602.Fortunately, these vibrational wave speeds should be faster than theskier's speed, and thus appear at a much shorter delay time on thecorrelation plot: the characteristic wave speed in aluminum is 20,664feet/sec, in ice about 10,496 feet/sec, and in rubber about 7872feet/sec for compressional waves. The bending wave speed will typicallybe slower, but can only be computed for well known geometries andmaterial compositions, and is usually easier to measure in the labbeforehand. If there should ever be a problem in measuring the speed Vvia the cross correlation of equation (2), it will likely beattributable to this. Should that problem occur, one can readily getaround it by changing the sensor spacing D, which would thence change τ.

[0358] The cross correlation is computed from digital samples via$\begin{matrix}{{{R_{12}\left( {r\quad \Delta \quad t} \right)} = {\frac{1}{N - r}{\sum\limits_{n = 1}^{N - r}\quad {s_{2,n}s_{1,{n + r}}}}}},} & (4)\end{matrix}$

[0359] where r defines the sample lag number at which the crosscorrelation is being computed, N the number of sample points in the timerecords, and the subscript n denotes the n-th element in the timerecord, and Δt is the sampling rate of the system. This function can benormalized to have unit magnitude by dividing through by the squareroots of the zero-delay auto correlations of the signals s₁ and s₂(e.g., the variances of these signals): $\begin{matrix}{{\rho \left( {r\quad \Delta \quad t} \right)} = \frac{R_{12}\left( {r\quad \Delta \quad t} \right)}{\sqrt{R_{1}(0)}\sqrt{R_{2}(0)}}} & (5)\end{matrix}$

[0360] for $\begin{matrix}{{R_{1} = {\frac{1}{N}{\sum\limits_{n = 1}^{N}\quad \left( s_{1,n} \right)^{2}}}};{R_{2} = {\frac{1}{N}{\sum\limits_{n = 1}^{N}\quad {\left( s_{2,n} \right)^{2}.}}}}} & (6)\end{matrix}$

[0361] This simplifies the setting of thresholds for selecting the delaytime τ corresponding to the skier speed V. Also, one can restrict theset of lag numbers r if you already have some idea of the expecteddelays, given the speeds you expect to encounter skiing or boarding (orother sports, since these techniques apply to other sports and arediscussed in the context of skiing for illustrative purposes only).

[0362] The means to test this measurement and processing methodology isto mount sensors on the board or ski, and first measure the correlationfunction of equation (4) for all r. Then, compute the speed V perequation (1), and compare it to that measured with a truth sensor, suchas a police radar gun, or a simple wind anemometer. Also, compute thestandard cross spectra function as found on most any spectrum analyzerto see if the phase of the cross spectra denotes a pure lag (aprogressive phase shift when unwrapped) over a range of frequencies (aswould be expected here). This method though requires that you computetwo FFTs, do a complex multiplication, and then compute the phase via anarctangent, all in real-time. If you see several delay times in thecross correlation, as might be found for a particularly floppy set ofskis with a very, very slow bending wave speed, move the sensors and seeif these peaks shift so as to separate out the propagation delay due toskiing. The only limitation here is the spatial coherence length of thesnow/board interface, which needs to be observed experimentally.

[0363] Regarding expected delays, consider the Table 2 of delay times(in msec) for two separations: D=1.5 ft (as might be found in afoot-to-foot spacing on a board), and D=4 ft. The delay T1 correspondsto D=1.5 ft, and T2 corresponds to D=4 ft. TABLE 2 Delay processingtimes speed T1 (msec) T2 (msec) 5 204.5 545 10 102.2 272.7 15 68.2 181.820 51.2 136.5 25 41 109.3 30 34.1 90.7 35 29.2 77.9

[0364] Table 2 shows that to resolve the speed to within 5 mph, whichrepresents one suitable quantizer for speed sensing for the invention,one needs to be able to resolve a time delay at the higher speeds ofabout 5 msec for the short baseline (D=1.5 ft) case. To resolve thiswith a finess of, e.g., one part in 10, you must sample at 0.5 msec,which implies a bandwidth of 2 kHz for the short baseline system. Thisis not an onerous sampling requirement, especially in view of modernprocessing capability. Nonetheless, this is a 2 kHz sample rate on twochannels (i.e., for the two sensors), sampled with simultaneity betterthan 0.5 msec as well (e.g., easily achievable inter-channel skew, evenfor a system without simultaneous sample and hold amplifiers).

[0365] Another implementation issue is the fact that the system willlose tracking during airtime, or perhaps when carving an especiallyaggressive turn, especially in very soft snow. Thus, it is preferably toimplement a last estimate hold feature on the display of speedinformation: if the data is not good enough to update the speed (e.g.,if the signals drop below a certain level indicative of air, if an air“trigger signal” is used as a conditional trigger, or if the correlationthreshold level is not met), then continue to display the last valuemeasured.

[0366] Other speed measurement implementations are provided in FIGS.55-57. In FIG. 55, the two sensors 1604′ are integrated beneath asnowboarder's boots 1622, or even within the boots' soles. In FIG. 56, amultiplicity of sensors 1604″ is included with a ski 1620 (showing abinding 1622), and the cross correlation is computed across any pair soas to maximize the signal to noise ratio, or even to adapt to differingsnow conditions or skier speeds. In FIG. 57, a two-dimensional array ofsensors 1604′″ is shown arranged around the boot mounts 1640 of asnowboard 1642, where one may employ either “s₁-s₂” or “s₃-s₄” sensorpairs to measure V depending on which side of the board is dug in (so asto maximize the sensor signals). One may also employ either s₁-s₃ ors₂-s₄ to infer side-slip via correlation measurements as well.

[0367] An alternative speed measuring system 1650 is shown in FIGS. 58and 59, incorporating a down-looking Doppler system: system 1650utilizes “bistatic” sonar, while system 1650 a utilizes “monostatic”.All of the transducers 1654 and their operating frequencies are chosenso that the resulting acoustic fields 1656 have wavelengths larger thanthe transducer diameters, making the radiation and receive patternsbroad and overlapping. The transmitter (the “pinger”) 1654 a transmit apulse, a CW signal, or a band-limited FM signal, and the receiver 1654 bsenses this signal and infers speed from the associated Doppler shift.

[0368] The system in FIG. 59 is of particular interest, as it combinestransmit and receive functions in a single element, reducing cost.Further, if one uses a pulsed signal in this configuration, then onecould use it not only to sense Doppler, but distance and height too (byapplying a time gate to the return). A near gate would be set topreclude measuring random hops and skips, but will instead see true“air” when the ski/board is sufficiently high above the snow. Onerangefinding system manufactured by Polariod can function as such asystem, with electronics for under $10.

[0369] Other Techniques for Power Estimation

[0370] Power can be used to quantitatively establish “bragging rights”among users, allowing them to compare level of effort expended during arun, over the course of a day, etc.

[0371] Power is defined conventionally as the rate of energy transferinto or out of a system. As such, power is an instantaneous quantity,rather than an integrative measure. Consequently, power can bedetermined as that energy expended over a run, providing a suitablemetric to measure and report.

[0372] There are three chief components leading to energy expenditure insports such as skiing and snowboarding:

[0373] 1. Frictional resistance as the vehicle moves across itssupporting surface, impeding the motion of the vehicle;

[0374] 2. Air drag (both form drag and frictional resistance), impedingthe motion of the vehicle/operator system;

[0375] 3. Supporting the operator upright in the presence of externalforces, such as those encountered when skiing over moguls, riding amountain bike over rough terrain, or when countering the pull of a towrope when water skiing.

[0376] Frictional drag can be modeled in a variety of ways. Nominally,if the resistance is viscous in nature, then the retarding force islinearly proportional to the vehicles speed V:

F _(d) =c·V,  (1)

[0377] where “c” is the viscous drag coefficient, which should bedetermined empirically. Note that the frictional force is linearlyproportional to the velocity V; while in practice the proportionality isnonlinear, the approximation will suffice for present purposes. Thelinear coefficient can also be estimated, measured or ignored (sincepower units can be unitless and preferably correspond to suitablenumbers to compare multitudes of users in an easy manner). Fromconservation of energy, $\begin{matrix}{{{\frac{1}{2}m\quad V^{2}\sin^{2}\theta} = {{m\quad g\quad \Delta \quad h} - {\int_{0}^{t_{f}}{c\quad {V^{2}(t)}\sin^{2}\theta \quad {t}}}}},} & (2)\end{matrix}$

[0378] where θ is the angle of the slope, “m” is the mass of the user(e.g., skier+skis), and Δh is the vertical drop between gates. Since thevelocity profile is linear over time, $\begin{matrix}{{{\int_{0}^{t_{f}}{c\quad {V^{2}(t)}\sin^{2}\theta \quad {t}}} = {\frac{1}{3}{cV}^{2}\sin^{2}\theta \quad t_{f}}},} & (3)\end{matrix}$

[0379] and thence $\begin{matrix}{c = {{3\left\lbrack \frac{{m\quad g\quad \Delta \quad h} - \left( \frac{m\quad V^{2}\sin^{2}\theta}{2} \right)}{V^{2}\sin^{2}\theta \quad t_{f}} \right\rbrack}.}} & (4)\end{matrix}$

[0380] With respect to the impact on energy expenditure during theactivity, the instantaneous power loss is given by $\begin{matrix}{{P_{d}(t)} = \left\{ \begin{matrix}{{{{F_{d}(t)} \cdot {V(t)}} = {{cV}^{2}(t)}};} & {{vehicle}\quad {in}\quad {contact}} \\{0;} & {{vehicle}\quad {not}\quad {in}\quad {{contact}.}}\end{matrix} \right.} & (5)\end{matrix}$

[0381] Assuming that the frictional coefficient is constant over therun, then if one measures V(t), as discussed above or by some otherestimation, then the total energy expenditure due to friction over a runis given by $\begin{matrix}{{E_{d} = {\int_{0}^{t_{end}}{{P_{d}(t)}\quad {t}}}},} & (6)\end{matrix}$

[0382] where t_(end) is the finishing time.

[0383] The resistive force due to air frictional drag is in generalproportional to the square of the velocity, hence the energy loss over arun will be proportional to the time integral of this resistive forcetimes the velocity. The proportionality constant will in general bedifficult to estimate, or even measure. However, roughly it isproportional to a constant times the cross sectional (frontal) area ofthe user. One can get a first cut at this area by assuming that thewidth of a skier is a fixed proportion of their height, then from ameasurement of weight (measured, for example, using the FSR meanspreviously described) and a standard actuarial table for weight/heightcorrelation. Thus, $\begin{matrix}{{E_{a} = {{\int_{0}^{t_{end}}{{am}\quad {V^{3}(t)}\quad {t}}} \cong {\sum\limits_{i = 1}^{(\frac{t_{end}}{\Delta \quad t})}\quad {{am}\quad {V^{3}\left( t_{i} \right)}\quad \Delta \quad t}}}},} & (7)\end{matrix}$

[0384] where “m” is the mass of the skier. The proportionality constant“a” is set heuristically.

[0385] Finally, the contribution to energy expenditure from supportingthe operator upright in the presence of external forces can be estimatedusing a system 1666 of FIG. 60, where the user 1670 wears anaccelerometer 1671 around her waist, capable of measuring the verticalcomponent of acceleration Δy(t). Further, the ski/board/boot sole 1672has a force measuring means 1674 (as discussed herein) to measure theforce component “F”. The operator 1670 will be dissipating energy bybending their knees, decelerating the mass of their upper body. Sincethe legs can be though of as rigid links with rotary springs at the kneeand hip joints, the force due to this deceleration will be transmittedto the force sensing means (springs transmit forces). This, theinstantaneous power dissipated in maintaining a tuck is given by$\begin{matrix}{P_{b} = {{{F(t)} \cdot \frac{{y(t)}}{t}} = {{F(t)} \cdot {\int_{\quad}^{t}{{y^{''}\quad(t)}{{t}.}}}}}} & (8)\end{matrix}$

[0386] Note that this equation is not conditional with respect tovehicle contact as per equation (5) of this section, as the reactionforce F goes to zero when the vehicle leaves the surface. The energyexpended over a run due to this effort is then given by $\begin{matrix}{E_{b} = {\int_{0}^{t_{end}}{{F \cdot \left\lbrack {\int_{\quad}^{t}{{y^{''}(t)}\quad {t}}} \right\rbrack}\quad {{t}.}}}} & (9)\end{matrix}$

[0387] In total, the energy expended over a run is given as the sum ofthe three energy components:

E _(total) =E _(d) +E _(a) +E _(b).  (10)

[0388] Alternate systems to measure the skier's hip position y(t) (shownin FIG. 60) is provided in FIGS. 61 and 62. In FIG. 61, a flexibleelement 1680 is sewn into the skier's pants 1682, covering the leg 1684.A PVDF or NiTiNOL SMA strip 1686 is bonded to the element 1680, and willact as a large-area strain gage. When the skier bends his knees the gage1686 will stretch, and to first order this strain will be proportionalto the change in the leg's bend angle at the knee. By differentiatingthis signal one can obtain a signal proportional to the velocity y(t)depicted above, but without using an accelerometer. Since one need notintegrate this signal to compute velocity or displacement, the energyexpenditure is computed simply as a multiplication.

[0389] Still another system for power measurement is shown in FIG. 62 InFIG. 62, a force gage or compressive strain element 1700 is insertedinto the inside of a tongue 1702 of a ski boot 1704. When the skierleans forward, the force on the tongue 1702 increases to first order inproportion to the angle of the lower leg with respect to the ski/board.Thus, one can measure a signal indicative of the quantity y(t) bymeasuring the force on the boot's tongue. Once again, since one need notintegrate this signal to compute velocity or displacement, the energyexpenditure is computed as a multiplication.

[0390] Other Techniques for Drop Distance

[0391] In one aspect, instantaneous height above the surface (a relativerather than an absolute measurement) is provided by the system of FIG.59. By using a simple pulse output sound waveform, and applying a timegate to the acoustic return, the system can sense the distance of askier/boarder above the ground from the round-trip time it takes thesignal to return to the sensor. This provides a measure of the skier'sinstantaneous height.

[0392] Other Techniques for Airtime

[0393] Several alternative airtime sensors are next shown, including onenew signal processor to detect transients to provide a “trigger” or“gate” for estimating airtime.

[0394] With a FSR (Force Sensing Resistor) one can detect the presenceof a skier in the vehicle (for instance, in the bindings if positionedbeneath the boot and above the binding), the skier's weight, and whetherthe skier is being supported by a surface or is “airborne”. A typicalFSR 1800 is sketched in FIG. 63. FSRs can be purchased from IEEInterlink for $2-$4 each in small quantities depending on the aperturesize. These pads consist of interdigitated electrodes 1802 over asemi-conductive polymer ink 1804. The resistance between the electrodes1802 decreases nonlinearly as a function of applied compressive load,and they exhibit high sensitivity. A PSA layer is generally applied toone side; a further encapsulant (say of polyurethane) is desirable for aharsh/wet environments. A typical FSR signal conditioning circuit isshown in FIG. 64 that provides a voltage indicative of the FSR'schanging resistance. Unlike accelerometers or induced-strain sensors(such as the AMP PVDF sensors), FSRs sense static loads.

[0395] Consider FIGS. 65 and 66. An FSR described above is placed in theload path of the skier, either beneath the boot 1808, within the boot'sheel 1809, within the ski/board, or beneath the ski/board 1810.Consequently, when the skier 1812 stands on the ski/board 1810, and whenthe ski/board 1810 is on the ground, there is a reaction force FRpushing up against the skier 1812. This will be sensed by the FSR, asshown in FIG. 67, region “A”. When the skier 1812 is pushed by bumps andmoguls this force will change, as shown in region “B”, FIG. 67, owing toNewton's second law. When the skier/boarder 1812 leaves the ground, asshown in FIG. 66, then region “C” is realized and reaction forcediminishes to zero as an easily-sensed transient. This too will besensed by the FSR, as suggested in FIG. 67, region D of Trace I. TraceII of FIG. 67 is closer to zero force (if not actually equal zero) andcorresponds to the case whereupon there is no residual compression ofthe FSR due to the clamping load of the binding, if the sensor is in thebinding or boot heel (or due to residual mechanical stresses inducedduring manufacture if the sensor is embedded within the ski/board).Trace II, which shows a higher “residual” load, reflects when theseresidual stresses are present, and needs to be quantified if thetransient amplitude change in region “C” is to be use as a trigger orgate to the airtime estimation. The skier/boarder 1812 becomesreacquainted with the supporting surface in region “E”, as the reactionforce may now actually peak owing to the compressional transient; thistoo is measured by the FSR in the load path. The skier/boarder 1812returns to “normal” travel again in region “F”.

[0396] The output of the FSR can in all liklihood be low-pass filteredat around 20 Hz, since the latency in estimating liftoff can be about500 msec (i.e., a reasonable minimum airtime lower limit). Triggergeneration is effected using only a comparator or similar analogthresholding electronics based upon signal amplitude, and perhaps slewrate or hysteresis (probably not necessary); and there is no need tomeasure spectral changes. Unfortunately, FSRs do not have significantbandwidth and thus can limit the measurable vehicle speed.

[0397] In the user of PVDFs (i.e., the piezo foils discussed above),certain care should be taken. First, they are only capable of measuringdynamic signals: they will not measure a static load, or a staticdisplacement. For static measurements (such as inferring weight asdescribed above) or very low frequency measurements (typically below 5to 10 Hz), other sensors should be employed such as FSRs.

[0398] A second performance limitation of the PVDF is that these sensorsare far more sensitive to induced in-plane strains than to compressionalstrains. These strain axes 1-3 are defined in FIG. 68, showing one piezofoil 1900. The in-plane strains are in the “1” and “2” directions, withthe “1” direction being the “pull” direction for the PVDF (almost alwaysthe long axis for the AMP sensing strips) associated with the material'sprocessing. The compressional strain is in the “3” direction. Note thatthe electromechanical constituitive constants relating an input strainto an output voltage measured across the thickness of the sensor (wherethe electrodes are always placed) are approximately an order ofmagnitude larger in the “1” direction than in the “3” direction; whilethe values in the “2” and “3” directions are approximately equal. Thisis an artifact of the fabrication methodology for so-called “uniaxial”PVDF. Consequently, this makes the AMP PVDF strips excellent dynamicstrain gages.

[0399] This enhanced strain performance is not a problem if the sensorstrip is attached to a rigid, non-bending surface, as suggested above(e.g., the housing 32, FIG. 1A). In this configuration the piezo isrigidly glued to an inflexible surface 1910, FIG. 69, and a rigid mass Mis attached to the top of the piezo 1912. Consequently, when the lowersurface is vibrated, the mass M causes the piezo 1912 to compress owingto the inertial forces, leading to a voltage output ΔV across thesensor's thickness proportional to the vibration, which is essentiallyhow an accelerometer works.

[0400] Consider a piezo strip 1920 attached to a flexible surface 1922,as suggested in FIG. 70. When the surface bends in response to an inputvibration, this induces an output in the sensor ΔV proportional to thebending strain. The vibration need not accelerate the mass M in thevertical direction to induce this output; so, if the surface is a ski,and the ski flexes irrespective of whether or not the ski is acceleratedvertically, you will measure an output that will typically swamp anysignal due to vertical acceleration or vibration. In this situation, youare measuring the flexural response of the ski, and not the verticalvibration induced by the ski's passage over a rough surface. In order tomeasure this vertical vibration, one needs to deconvolve the ski'sflexural dynamics, a significant challenge. Note also that the skiitself is acting as a filter, since it has natural modes of responsemuch like a guitar string or drum head, and very much wants to respondat those frequencies. This will skew and perhaps dominate anymeasurement of the vibrational spectra.

[0401] These problems are addressed in FIGS. 71 and 72. Consider a skior snowboard having two PVDF sensors deposited on it, one atop the skiand one below (or any symmetric arrangement about the midline of theski/board), registered spatially one above the other. These are laid upwith their polarization axes aligned, as suggested by the arrows inFIGS. 71, 72. In FIG. 71, the ski bends, and the top sensor sees acompressive strain, while the lower sees an extensive strain. Thus,charge will migrate to the outer surfaces of both piezos. If onemeasures the voltage potential across these two sensors the result willbe (ideally) zero; the same is true for bending in the oppositedirection, for higher-order modes, etc. In practice, the bending strainresponse is significantly diminished, with residual response due tomis-matched sensors and positioning errors. One can think of thisarrangement as providing “common mode rejection” for bending strains. InFIG. 72, if a compressive stress is applied as from a verticalacceleration of the ski owing to its passage over an irregular surfacethen a potential difference is induced over the outer layers of thesensor composite, and a voltage V is measured.

[0402] An alternate means of achieving an analogous result on one sideof the vehicle is to build a sandwich of two PVDF layers, as shown inFIG. 73. Here, the polarization axes are aligned in opposition. Unlikethe previous embodiment, this arrangement's voltage output is measuredvia the connections shown at the left side 1980 of the sensor 1982,which tap both the inner and outer electrodes of the piezo composite.This arrangement has proven to yield a superior acoustic receiver, andprovides common mode rejection to electrical interference such as fromradio transmitters.

[0403] For both embodiments of FIGS. 71172 and 73, one can employ avoltage-follower circuit to drive long leads, if required.

[0404]FIG. 74 illustrates a gaming system 2200 which connects severalmountains 2202 a-2202 c via a WAN or the Internet 2208. A pluralityskier or snowboarder 2204 are on the mountains 2202; and each has a datatransmitting device 2206 (the device is illustrated in FIG. 75); andeach device 2206 includes functionality such as described herein toprovide performance data. In particular, each device 2206 includes amicroprocessor 2208 (or microcontroller or other intelligence sufficientto assist in acquiring data from connected transducers) and can includeone or more of the following: airtime sensor 2210 a, speed sensor 2210b, power sensor 2210 c and drop distance sensor 2210 d. If required, abattery drives the device 2206. The microprocessor 2208 collects datafrom one or more sensors 2210 (note that sensors 2210 can be simpletransducers connected through conditioning electronics 2212), processesthe data, and transmits the data to a data driver 2214, such as datasection 22, FIG. 1A. The data driver 2214 communicates with receivers(e.g., the receiver 72, FIG. 1B) at each respective lodge 2220 a-1220 cso that the data is available on the Internet 2208. In this manner, datafrom any mountain is collected for comparison to other players on othermountains. A main database 2222 keeps and stores all data for accessthrough the Internet 2208. For example, the database 2222 can include aWWW interface which all can access (if desired, or only if give accessauthority) to acquire and compare scores across the nation (or world).

[0405] Note that the game played by the system 2200 can be for airtime,speed, power, or drop distance, or a combination of one or more.Further, it should be understood that the medium of skiing is shownillustratively, and that other sports are easily accomplished in asimilar system. By way of example, each person 2204 could be a mountainbiker instead. Or, each mountain could be replaced by a lake or oceanand each person 2204 can be a windsurfer.

[0406] Certain devices of the invention can also be incorporated into aboot binding, such as shown in FIGS. 76 and 77. In FIG. 76, a skibinding 2300 is shown; while in FIG. 77, a snowboarder binding 2302 isshown. In each case, a sensing unit 2304 such as described above isincorporated into the binding. The device 2304 can include, for example,an airtime device and/or a power sensor and/or a pitch-based speedsensor and/or an altimeter. A data transfer unit 2306 (e.g., a radio,inductive loop, IR transmitter) connects to the unit 2304 so that data(e.g., airtime, power, speed and drop distance) can be relayed to theuser (or to a data unit or to the base station). For example, the usercarries a sister data receive unit (not shown) that provides the userwith the desired data. Note that data transfer unit can be an IRtransmitting section and the receive data unit can be a datawatch, suchas described above. The device 2304 includes power and other circuitryso as to operate and acquire the appropriate data, as described above.

[0407] The advantage of the design of FIG. 76 is that a sensing unitaccording to the invention is not mounted directly on the ski (orsnowboard) and is further protected from the environment. Also, it ismore practical to mounting to a board or ski. Without such packagingadvantage, it is difficult, though not impossible, to package a sensingunit (such as an air meter or speed meter, described herein) onto aboard with sufficiently small size and weight. Preferably, a device suchas the device 1102 of FIG. 41 has only a depth of 0.300″ or less, and anoverall weight of less than ⅛ to ¼ pound. Such a size is preferred inorder to fit the device into a recessed area on the board withoutexcessive overhang or add-on weight. However, as in FIG. 77, this goalis relaxed somewhat.

[0408] Power can also be determined by other methods, in accord with theinvention. For example, with an accelerometer pointed up, relative tothe ski and perpendicular to the ground, when the user hits bumpyterrain, the accelerometer will have “peaks” and valleys. One techniquefor determining power is thus to count peaks past some predeterminedthreshold, such as shown in FIG. 78, which illustrates “5” peak signalswhich pass the threshold “k”. The value “5” does not have to correspondto a real unit, such as g's. The value of k can be set experimentallysuch as through the data unit described above. k should be above 1 G,for example, which is a constant force. That is, when the accelerometeris not pointed along the gravity vector, it might read “0” and will read“1”—and neither event should effect the power calculation.Alternatively, an exact determination of g's can be made and provided bythe sensor, and thus given to the user. However, this requires extensiveprocessing and is not overly practical. The goal here is to displayunits that are common to all. For example, power units could extend from0-10 (or 0-100) wherein, for example, a user with a 9 shows greatexertion as compared to a user with a “1” reading (or alternatively, a70 as compared to a 10 reading). It is thus important to make the powerdetermination at appropriate intervals, or at a set integration time.

[0409]FIG. 79 shows a sensor 2499 such as described herein including adoppler module 2500. The beam 2502 from the module 2500 extendsbackwards, or forwards, on the ski (or snowboard) 2506 and about 45degrees to the side. In this manner, the beam 2502 need not extendthrough the board, such as described above; but can instead broadlyilluminate a region 2504 away from the ski 2506. Since the module 2500is slightly above the board, it can illuminate the region 2504 withoutgoing through the board 2506. This greatly assists taking suchmeasurements, for example, in the ultrasound region since ultrasounddoes not transmit through boards well. Similarly, for microwave, metalin the board can completely wipe out a signal return, effectivelyeliminating the speed measurement.

[0410] It should be noted that a power sensing unit can be madegenerically and simply on a wrist watch, as discussed above. Such a unitis useful for various sports, such as basketball, to monitor a user'saggressiveness in play. As shown in FIG. 80, such a unit in the form ofa watch 2600 can provide data to a computer 2602 at the gaming site(FIG. 80 shows one user on a basketball court, for example; though thescene is equally applicable to other sports, e.g., soccer, football andhockey). The computer 2602 and watch 2600 have data transfer capabilitysuch as through RF signals, known to those in the art. During play, theuser 2604 is effectively “monitored” so that the coach or owner caneffectively gauge performance and aggressiveness. The device within thewatch 2600 can include sensors such as described herein. The watch 2600further includes batteries and required circuitry.

[0411] The unit 2600′ could also be placed and/or sewn into a user'sshorts, as shown in FIG. 81.

[0412] Certain sensing units of the invention require power. Often it isdesirable to turn the power off when the unit is not in use, such aswhen the user is in a bar. In accord with the invention, a FET switchcan be used for this purpose, such as known in the art. This savesbattery life.

[0413] Power and/or speed can also be measured and assessed by measuringsignal [PSD] power spectral density.

[0414] Barometers and altimeters, in accord with the invention,preferably “logic” out data at the base and peak of a mountain, so thatdata is not stored and recorded in these regions. This is similar tologic out regions such as airtime above 30 seconds, which likely doesnot occur, or for less than 1 second (or 2 second) which resembleswalking and which should be ignored.

[0415] Note, if there is no airtime, often, the circuitry of theinvention should operate to logic out drop distance too, such as shownin FIG. 82.

[0416]FIG. 83 illustrates one other embodiment wherein data from asensor 2699 such as described herein (e.g., a sensor such as an airtimesensor) transmits data to a user 2700 at the user's helmet 2702. Aheads-up display 2704 and/or a microphone 2706 can be used to relayperformance data to the user 2700, for example by informing the user of“airtime”. If the user is a speed skier, the data is useful to modifyform since they do not wish airtime. A base station computer can alsomonitor the airtime data which can then be evaluated later. A buzz sentto the mic 2706 can similarly inform the user 1700. The heads-up display2704 can take the form of sunglasses; and the helmet 2702 is notrequired.

[0417] Sensing units of the invention can be integrated within manysports implements, such as shown in FIG. 84. Each implement of FIG. 84includes a sensing unit 3000, described herein. The implements include,at least, ice skates, water skis 3004 (or wakeboards 3004), ski poles3006, windsurfer 3008, surfboard 3010, tennis racquet 3012, skateboard3014, roller blade 3016, and volleyball 3018. Other implements arewithin the scope of the invention.

[0418] Those skilled in the art should appreciate that changes can bemade within the description above without departing from the scope ofthe invention.

[0419] The invention thus attains the objects set forth above, amongthose apparent from preceding description. Since certain changes may bemade in the above apparatus and methods without departing from the scopeof the invention, it is intended that all matter contained in the abovedescription or shown in the accompanying drawing be interpreted asillustrative and not in a limiting sense.

[0420] It is also to be understood that the following claims are tocover all generic and specific features of the invention describedherein, and all statements of the scope of the invention which, as amatter of language, might be said to fall there between.

We claim:
 1. A system for comparing athletic performance between multiple persons, comprising: a mobile sensor for each of the persons; a database for downloading data generated by the mobile sensor and processing the data to compare athletic performances of the multiple persons, the database being accessible through the Internet to review the athletic performances between the persons.
 2. The system of claim 1, wherein the mobile sensor comprises a wireless transmitter as wirelessly communicating between the mobile sensor and a wireless receiver connected with the database.
 3. The system of claim 1, the mobile sensor comprising a speed sensor, the athletic performances comprising speed associated with the persons.
 4. The system of claim 3, the speed sensor comprising an altimeter used to determine the speed.
 5. The system of claim 3, the speed sensor comprising a pressure sensor used to determine the speed.
 6. The system of claim 1, the mobile sensor comprising an airtime sensor, the athletic performances comprising airtimes associated with the persons.
 7. The system of claim 1, the mobile sensor comprising a drop distance sensor, the athletic performances comprising drop distances associated with the persons.
 8. The system of claim 1, the mobile sensor comprising a mobile power sensor, the athletic performances comprising power associated with the persons.
 9. The system of claim 8, the mobile power sensor determining an amount of energy expended by each of the persons during athletic activity.
 10. The system of claim 8, the mobile power sensor determining an amount of impact energy received by each of the persons during athletic activity.
 11. The system of claim 8, the mobile power sensor determining an aggressiveness corresponding to motion of each of the persons during athletic activity.
 12. The method of claim 1, the mobile sensor comprising a watch.
 13. The system of claim 1, the database processing the data to compare velocity of each of the persons.
 14. The system of claim 1, the mobile sensor configurable to attach to a body or clothing of an individual.
 15. The system of claim 1, the database processing the data to compare altitude variation between each of the persons.
 16. The system of claim 1, the mobile sensor comprising a GPS receiver.
 17. The system of claim 1, the mobile sensor concurrently communicating wireless data from the multiple persons. 